


 Floatingpoint unit for Microwatt








library ieee;




use ieee.std_logic_1164.all;




use ieee.numeric_std.all;








library work;




use work.insn_helpers.all;




use work.decode_types.all;




use work.crhelpers.all;




use work.helpers.all;




use work.common.all;








entity fpu is




port (




clk : in std_ulogic;




rst : in std_ulogic;




flush_in : in std_ulogic;








e_in : in Execute1ToFPUType;




e_out : out FPUToExecute1Type;








w_out : out FPUToWritebackType




);




end entity fpu;








architecture behaviour of fpu is




type fp_number_class is (ZERO, FINITE, INFINITY, NAN);








constant EXP_BITS : natural := 13;




constant UNIT_BIT : natural := 56;




constant QNAN_BIT : natural := UNIT_BIT  1;




constant SP_LSB : natural := UNIT_BIT  23;




constant SP_GBIT : natural := SP_LSB  1;




constant SP_RBIT : natural := SP_LSB  2;




constant DP_LSB : natural := UNIT_BIT  52;




constant DP_GBIT : natural := DP_LSB  1;




constant DP_RBIT : natural := DP_LSB  2;








type fpu_reg_type is record




class : fp_number_class;




negative : std_ulogic;




denorm : std_ulogic;




exponent : signed(EXP_BITS1 downto 0);  unbiased




mantissa : std_ulogic_vector(63 downto 0);  8.56 format




end record;








type state_t is (IDLE, DO_ILLEGAL,




DO_MCRFS, DO_MTFSB, DO_MTFSFI, DO_MFFS, DO_MTFSF,




DO_FMR, DO_FMRG, DO_FCMP, DO_FTDIV, DO_FTSQRT,




DO_FCFID, DO_FCTI,




DO_FRSP, DO_FRI,




DO_FADD, DO_FMUL, DO_FDIV, DO_FSQRT, DO_FMADD,




DO_FRE, DO_FRSQRTE,




DO_FSEL,




DO_IDIVMOD,




FRI_1,




ADD_1, ADD_SHIFT, ADD_2, ADD_3,




CMP_1, CMP_2,




MULT_1,




FMADD_0, FMADD_1, FMADD_2, FMADD_3,




FMADD_4, FMADD_5, FMADD_6,




LOOKUP,




DIV_2, DIV_3, DIV_4, DIV_5, DIV_6,




FRE_1,




RSQRT_1,




FTDIV_1,




SQRT_1, SQRT_2, SQRT_3, SQRT_4,




SQRT_5, SQRT_6, SQRT_7, SQRT_8,




SQRT_9, SQRT_10, SQRT_11, SQRT_12,




INT_SHIFT, INT_ROUND, INT_ISHIFT,




INT_FINAL, INT_CHECK, INT_OFLOW,

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



FINISH, NORMALIZE,




ROUND_UFLOW, ROUND_OFLOW,




ROUNDING, ROUNDING_2, ROUNDING_3,




DENORM,




RENORM_A, RENORM_A2,




RENORM_B, RENORM_B2,




RENORM_C, RENORM_C2,




NAN_RESULT, EXC_RESULT,




IDIV_NORMB, IDIV_NORMB2, IDIV_NORMB3,




IDIV_CLZA, IDIV_CLZA2, IDIV_CLZA3,




IDIV_NR0, IDIV_NR1, IDIV_NR2, IDIV_USE0_5,




IDIV_DODIV, IDIV_SH32,




IDIV_DIV, IDIV_DIV2, IDIV_DIV3, IDIV_DIV4, IDIV_DIV5,




IDIV_DIV6, IDIV_DIV7, IDIV_DIV8, IDIV_DIV9,




IDIV_EXT_TBH, IDIV_EXT_TBH2, IDIV_EXT_TBH3,




IDIV_EXT_TBH4, IDIV_EXT_TBH5,




IDIV_EXTDIV, IDIV_EXTDIV1, IDIV_EXTDIV2, IDIV_EXTDIV3,




IDIV_EXTDIV4, IDIV_EXTDIV5, IDIV_EXTDIV6,




IDIV_MODADJ, IDIV_MODSUB, IDIV_DIVADJ, IDIV_OVFCHK, IDIV_DONE, IDIV_ZERO);








type decode32 is array(0 to 31) of state_t;




type decode8 is array(0 to 7) of state_t;








type reg_type is record




state : state_t;




busy : std_ulogic;




f2stall : std_ulogic;




instr_done : std_ulogic;




complete : std_ulogic;




do_intr : std_ulogic;




illegal : std_ulogic;




op : insn_type_t;




insn : std_ulogic_vector(31 downto 0);




instr_tag : instr_tag_t;




dest_fpr : gspr_index_t;




fe_mode : std_ulogic;




rc : std_ulogic;




fp_rc : std_ulogic;




is_cmp : std_ulogic;




single_prec : std_ulogic;




sp_result : std_ulogic;




fpscr : std_ulogic_vector(31 downto 0);




comm_fpscr : std_ulogic_vector(31 downto 0);  committed FPSCR value




a : fpu_reg_type;




b : fpu_reg_type;




c : fpu_reg_type;




r : std_ulogic_vector(63 downto 0);  8.56 format




s : std_ulogic_vector(55 downto 0);  extended fraction

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



x : std_ulogic;




p : std_ulogic_vector(63 downto 0);  8.56 format




y : std_ulogic_vector(63 downto 0);  8.56 format




result_sign : std_ulogic;




result_class : fp_number_class;




result_exp : signed(EXP_BITS1 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



shift : signed(EXP_BITS1 downto 0);




writing_fpr : std_ulogic;




write_reg : gspr_index_t;




complete_tag : instr_tag_t;




writing_cr : std_ulogic;




writing_xer : std_ulogic;




int_result : std_ulogic;




cr_result : std_ulogic_vector(3 downto 0);




cr_mask : std_ulogic_vector(7 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



old_exc : std_ulogic_vector(4 downto 0);




update_fprf : std_ulogic;




quieten_nan : std_ulogic;




nsnan_result : std_ulogic;

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



tiny : std_ulogic;




denorm : std_ulogic;




round_mode : std_ulogic_vector(2 downto 0);




is_subtract : std_ulogic;




exp_cmp : std_ulogic;




madd_cmp : std_ulogic;




add_bsmall : std_ulogic;




is_multiply : std_ulogic;




is_sqrt : std_ulogic;




first : std_ulogic;




count : unsigned(1 downto 0);




doing_ftdiv : std_ulogic_vector(1 downto 0);




opsel_a : std_ulogic_vector(1 downto 0);




use_a : std_ulogic;




use_b : std_ulogic;




use_c : std_ulogic;




invalid : std_ulogic;




negate : std_ulogic;




longmask : std_ulogic;




integer_op : std_ulogic;




divext : std_ulogic;




divmod : std_ulogic;




is_signed : std_ulogic;




int_ovf : std_ulogic;




div_close : std_ulogic;




inc_quot : std_ulogic;




a_hi : std_ulogic_vector(7 downto 0);




a_lo : std_ulogic_vector(55 downto 0);




m32b : std_ulogic;




oe : std_ulogic;




xerc : xer_common_t;




xerc_result : xer_common_t;




res_negate : std_ulogic;




res_subtract : std_ulogic;




res_rmode : std_ulogic_vector(2 downto 0);




end record;








type lookup_table is array(0 to 1023) of std_ulogic_vector(17 downto 0);








signal r, rin : reg_type;








signal fp_result : std_ulogic_vector(63 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



signal opsel_b : std_ulogic_vector(1 downto 0);




signal opsel_r : std_ulogic_vector(1 downto 0);




signal opsel_s : std_ulogic_vector(1 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



signal opsel_ainv : std_ulogic;




signal opsel_mask : std_ulogic;




signal opsel_binv : std_ulogic;

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



signal in_a : std_ulogic_vector(63 downto 0);




signal in_b : std_ulogic_vector(63 downto 0);




signal result : std_ulogic_vector(63 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



signal carry_in : std_ulogic;




signal lost_bits : std_ulogic;




signal r_hi_nz : std_ulogic;




signal r_lo_nz : std_ulogic;




signal r_gt_1 : std_ulogic;




signal s_nz : std_ulogic;

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



signal misc_sel : std_ulogic_vector(3 downto 0);




signal f_to_multiply : MultiplyInputType;




signal multiply_to_f : MultiplyOutputType;




signal msel_1 : std_ulogic_vector(1 downto 0);




signal msel_2 : std_ulogic_vector(1 downto 0);




signal msel_add : std_ulogic_vector(1 downto 0);




signal msel_inv : std_ulogic;




signal inverse_est : std_ulogic_vector(18 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago







 opsel values




constant AIN_R : std_ulogic_vector(1 downto 0) := "00";




constant AIN_A : std_ulogic_vector(1 downto 0) := "01";




constant AIN_B : std_ulogic_vector(1 downto 0) := "10";




constant AIN_C : std_ulogic_vector(1 downto 0) := "11";

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago







constant BIN_ZERO : std_ulogic_vector(1 downto 0) := "00";




constant BIN_R : std_ulogic_vector(1 downto 0) := "01";




constant BIN_RND : std_ulogic_vector(1 downto 0) := "10";




constant BIN_PS8 : std_ulogic_vector(1 downto 0) := "11";

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago







constant RES_SUM : std_ulogic_vector(1 downto 0) := "00";




constant RES_SHIFT : std_ulogic_vector(1 downto 0) := "01";




constant RES_MULT : std_ulogic_vector(1 downto 0) := "10";

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



constant RES_MISC : std_ulogic_vector(1 downto 0) := "11";








constant S_ZERO : std_ulogic_vector(1 downto 0) := "00";




constant S_NEG : std_ulogic_vector(1 downto 0) := "01";




constant S_SHIFT : std_ulogic_vector(1 downto 0) := "10";




constant S_MULT : std_ulogic_vector(1 downto 0) := "11";








 msel values




constant MUL1_A : std_ulogic_vector(1 downto 0) := "00";




constant MUL1_B : std_ulogic_vector(1 downto 0) := "01";




constant MUL1_Y : std_ulogic_vector(1 downto 0) := "10";




constant MUL1_R : std_ulogic_vector(1 downto 0) := "11";








constant MUL2_C : std_ulogic_vector(1 downto 0) := "00";




constant MUL2_LUT : std_ulogic_vector(1 downto 0) := "01";




constant MUL2_P : std_ulogic_vector(1 downto 0) := "10";




constant MUL2_R : std_ulogic_vector(1 downto 0) := "11";








constant MULADD_ZERO : std_ulogic_vector(1 downto 0) := "00";




constant MULADD_CONST : std_ulogic_vector(1 downto 0) := "01";




constant MULADD_A : std_ulogic_vector(1 downto 0) := "10";




constant MULADD_RS : std_ulogic_vector(1 downto 0) := "11";





FPU: Make an explicit exponent data path
With this, the large case statement sets values for a set of control
signals, which then control multiplexers and adders that generate
values for v.result_exp and v.shift. The plan is for the case
statement to turn into a microcode ROM eventually.
The value of v.result_exp is the sum of two values, either of which
can be negated (but not both). The first value can be chosen from the
result exponent, A exponent, B exponent arithmetically shifted right
one bit, or 0. The second value can be chosen from new_exp (which is
r.result_exp  r.shift), B exponent, C exponent or a constant. The
choices for the constant are 0, 56, the maximum exponent (max_exp) or
the exponent bias for trapenabled overflow conditions (bias_exp).
These choices are controlled by the signals re_sel1, re_neg1, re_sel2
and re_neg2, and the sum is written into v.result_exp if re_set_result
is 1.
For v.shift we also compute the sum of two values, either of which
can be negated (but not both). The first value can be chosen from
new_exp, B exponent, r.shift, or 0. The second value can be chosen
from the A exponent or a constant. The possible constants are 0, 1,
4, 8, 32, 52, 56, 63, 64, or the minimum exponent (min_exp). These
choices are controlled by the signals rs_sel1, rs_neg1, rs_sel2 and
rs_neg2. After the adder there is a multiplexer which selects either
the sum or a shift count for normalization (derived from a count
leading zeroes operation on R) to be written into v.shift. The
countleadingzeroes result does not go through the adder for timing
reasons.
In order to simplify the logic and help improve timing, settings of
the control signals have been made unconditional in a state in many
places, even if those settings are only required when some condition
is met.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
2 years ago



 control signals and values for exponent data path




constant REXP1_ZERO : std_ulogic_vector(1 downto 0) := "00";




constant REXP1_R : std_ulogic_vector(1 downto 0) := "01";




constant REXP1_A : std_ulogic_vector(1 downto 0) := "10";




constant REXP1_BHALF : std_ulogic_vector(1 downto 0) := "11";








constant REXP2_CON : std_ulogic_vector(1 downto 0) := "00";




constant REXP2_NE : std_ulogic_vector(1 downto 0) := "01";




constant REXP2_C : std_ulogic_vector(1 downto 0) := "10";




constant REXP2_B : std_ulogic_vector(1 downto 0) := "11";








constant RECON2_ZERO : std_ulogic_vector(1 downto 0) := "00";




constant RECON2_UNIT : std_ulogic_vector(1 downto 0) := "01";




constant RECON2_BIAS : std_ulogic_vector(1 downto 0) := "10";




constant RECON2_MAX : std_ulogic_vector(1 downto 0) := "11";








signal re_sel1 : std_ulogic_vector(1 downto 0);




signal re_sel2 : std_ulogic_vector(1 downto 0);




signal re_con2 : std_ulogic_vector(1 downto 0);




signal re_neg1 : std_ulogic;




signal re_neg2 : std_ulogic;




signal re_set_result : std_ulogic;








constant RSH1_ZERO : std_ulogic_vector(1 downto 0) := "00";




constant RSH1_B : std_ulogic_vector(1 downto 0) := "01";




constant RSH1_NE : std_ulogic_vector(1 downto 0) := "10";




constant RSH1_S : std_ulogic_vector(1 downto 0) := "11";








constant RSH2_CON : std_ulogic := '0';




constant RSH2_A : std_ulogic := '1';








constant RSCON2_ZERO : std_ulogic_vector(3 downto 0) := "0000";




constant RSCON2_1 : std_ulogic_vector(3 downto 0) := "0001";




constant RSCON2_UNIT_52 : std_ulogic_vector(3 downto 0) := "0010";




constant RSCON2_64_UNIT : std_ulogic_vector(3 downto 0) := "0011";




constant RSCON2_32 : std_ulogic_vector(3 downto 0) := "0100";




constant RSCON2_52 : std_ulogic_vector(3 downto 0) := "0101";




constant RSCON2_UNIT : std_ulogic_vector(3 downto 0) := "0110";




constant RSCON2_63 : std_ulogic_vector(3 downto 0) := "0111";




constant RSCON2_64 : std_ulogic_vector(3 downto 0) := "1000";




constant RSCON2_MINEXP : std_ulogic_vector(3 downto 0) := "1001";








signal rs_sel1 : std_ulogic_vector(1 downto 0);




signal rs_sel2 : std_ulogic;




signal rs_con2 : std_ulogic_vector(3 downto 0);




signal rs_neg1 : std_ulogic;




signal rs_neg2 : std_ulogic;




signal rs_norm : std_ulogic;








constant arith_decode : decode32 := (




 indexed by bits 5..1 of opcode




2#01000# => DO_FRI,




2#01100# => DO_FRSP,




2#01110# => DO_FCTI,




2#01111# => DO_FCTI,




2#10010# => DO_FDIV,




2#10100# => DO_FADD,




2#10101# => DO_FADD,




2#10110# => DO_FSQRT,




2#11000# => DO_FRE,




2#11001# => DO_FMUL,




2#11010# => DO_FRSQRTE,




2#11100# => DO_FMADD,




2#11101# => DO_FMADD,




2#11110# => DO_FMADD,




2#11111# => DO_FMADD,




others => DO_ILLEGAL




);








constant cmp_decode : decode8 := (




2#000# => DO_FCMP,




2#001# => DO_FCMP,




2#010# => DO_MCRFS,




2#100# => DO_FTDIV,




2#101# => DO_FTSQRT,




others => DO_ILLEGAL




);








constant misc_decode : decode32 := (




 indexed by bits 10, 8, 4, 2, 1 of opcode




2#00010# => DO_MTFSB,




2#01010# => DO_MTFSFI,




2#10010# => DO_FMRG,




2#11010# => DO_FMRG,




2#10011# => DO_MFFS,




2#11011# => DO_MTFSF,




2#10110# => DO_FCFID,




2#11110# => DO_FCFID,




others => DO_ILLEGAL




);








 Inverse lookup table, indexed by the top 8 fraction bits




 The first 256 entries are the reciprocal (1/x) lookup table,




 and the remaining 768 entries are the reciprocal square root table.




 Output range is [0.5, 1) in 0.19 format, though the top




 bit isn't stored since it is always 1.




 Each output value is the inverse of the center of the input




 range for the value, i.e. entry 0 is 1 / (1 + 1/512),




 entry 1 is 1 / (1 + 3/512), etc.




constant inverse_table : lookup_table := (




 1/x lookup table




 Unit bit is assumed to be 1, so input range is [1, 2)




18x"3fc01", 18x"3f411", 18x"3ec31", 18x"3e460", 18x"3dc9f", 18x"3d4ec", 18x"3cd49", 18x"3c5b5",




18x"3be2f", 18x"3b6b8", 18x"3af4f", 18x"3a7f4", 18x"3a0a7", 18x"39968", 18x"39237", 18x"38b14",




18x"383fe", 18x"37cf5", 18x"375f9", 18x"36f0a", 18x"36828", 18x"36153", 18x"35a8a", 18x"353ce",




18x"34d1e", 18x"3467a", 18x"33fe3", 18x"33957", 18x"332d7", 18x"32c62", 18x"325f9", 18x"31f9c",




18x"3194a", 18x"31303", 18x"30cc7", 18x"30696", 18x"30070", 18x"2fa54", 18x"2f443", 18x"2ee3d",




18x"2e841", 18x"2e250", 18x"2dc68", 18x"2d68b", 18x"2d0b8", 18x"2caee", 18x"2c52e", 18x"2bf79",




18x"2b9cc", 18x"2b429", 18x"2ae90", 18x"2a900", 18x"2a379", 18x"29dfb", 18x"29887", 18x"2931b",




18x"28db8", 18x"2885e", 18x"2830d", 18x"27dc4", 18x"27884", 18x"2734d", 18x"26e1d", 18x"268f6",




18x"263d8", 18x"25ec1", 18x"259b3", 18x"254ac", 18x"24fad", 18x"24ab7", 18x"245c8", 18x"240e1",




18x"23c01", 18x"23729", 18x"23259", 18x"22d90", 18x"228ce", 18x"22413", 18x"21f60", 18x"21ab4",




18x"2160f", 18x"21172", 18x"20cdb", 18x"2084b", 18x"203c2", 18x"1ff40", 18x"1fac4", 18x"1f64f",




18x"1f1e1", 18x"1ed79", 18x"1e918", 18x"1e4be", 18x"1e069", 18x"1dc1b", 18x"1d7d4", 18x"1d392",




18x"1cf57", 18x"1cb22", 18x"1c6f3", 18x"1c2ca", 18x"1bea7", 18x"1ba8a", 18x"1b672", 18x"1b261",




18x"1ae55", 18x"1aa50", 18x"1a64f", 18x"1a255", 18x"19e60", 18x"19a70", 18x"19686", 18x"192a2",




18x"18ec3", 18x"18ae9", 18x"18715", 18x"18345", 18x"17f7c", 18x"17bb7", 18x"177f7", 18x"1743d",




18x"17087", 18x"16cd7", 18x"1692c", 18x"16585", 18x"161e4", 18x"15e47", 18x"15ab0", 18x"1571d",




18x"1538e", 18x"15005", 18x"14c80", 18x"14900", 18x"14584", 18x"1420d", 18x"13e9b", 18x"13b2d",




18x"137c3", 18x"1345e", 18x"130fe", 18x"12da2", 18x"12a4a", 18x"126f6", 18x"123a7", 18x"1205c",




18x"11d15", 18x"119d2", 18x"11694", 18x"11359", 18x"11023", 18x"10cf1", 18x"109c2", 18x"10698",




18x"10372", 18x"10050", 18x"0fd31", 18x"0fa17", 18x"0f700", 18x"0f3ed", 18x"0f0de", 18x"0edd3",




18x"0eacb", 18x"0e7c7", 18x"0e4c7", 18x"0e1ca", 18x"0ded2", 18x"0dbdc", 18x"0d8eb", 18x"0d5fc",




18x"0d312", 18x"0d02b", 18x"0cd47", 18x"0ca67", 18x"0c78a", 18x"0c4b1", 18x"0c1db", 18x"0bf09",




18x"0bc3a", 18x"0b96e", 18x"0b6a5", 18x"0b3e0", 18x"0b11e", 18x"0ae5f", 18x"0aba3", 18x"0a8eb",




18x"0a636", 18x"0a383", 18x"0a0d4", 18x"09e28", 18x"09b80", 18x"098da", 18x"09637", 18x"09397",




18x"090fb", 18x"08e61", 18x"08bca", 18x"08936", 18x"086a5", 18x"08417", 18x"0818c", 18x"07f04",




18x"07c7e", 18x"079fc", 18x"0777c", 18x"074ff", 18x"07284", 18x"0700d", 18x"06d98", 18x"06b26",




18x"068b6", 18x"0664a", 18x"063e0", 18x"06178", 18x"05f13", 18x"05cb1", 18x"05a52", 18x"057f5",




18x"0559a", 18x"05342", 18x"050ed", 18x"04e9a", 18x"04c4a", 18x"049fc", 18x"047b0", 18x"04567",




18x"04321", 18x"040dd", 18x"03e9b", 18x"03c5c", 18x"03a1f", 18x"037e4", 18x"035ac", 18x"03376",




18x"03142", 18x"02f11", 18x"02ce2", 18x"02ab5", 18x"0288b", 18x"02663", 18x"0243d", 18x"02219",




18x"01ff7", 18x"01dd8", 18x"01bbb", 18x"019a0", 18x"01787", 18x"01570", 18x"0135b", 18x"01149",




18x"00f39", 18x"00d2a", 18x"00b1e", 18x"00914", 18x"0070c", 18x"00506", 18x"00302", 18x"00100",




 1/sqrt(x) lookup table




 Input is in the range [1, 4), i.e. two bits to the left of the




 binary point. Those 2 bits index the following 3 blocks of 256 values.




 1.0 ... 1.9999




18x"3fe00", 18x"3fa06", 18x"3f612", 18x"3f224", 18x"3ee3a", 18x"3ea58", 18x"3e67c", 18x"3e2a4",




18x"3ded2", 18x"3db06", 18x"3d73e", 18x"3d37e", 18x"3cfc2", 18x"3cc0a", 18x"3c85a", 18x"3c4ae",




18x"3c106", 18x"3bd64", 18x"3b9c8", 18x"3b630", 18x"3b29e", 18x"3af10", 18x"3ab86", 18x"3a802",




18x"3a484", 18x"3a108", 18x"39d94", 18x"39a22", 18x"396b6", 18x"3934e", 18x"38fea", 18x"38c8c",




18x"38932", 18x"385dc", 18x"3828a", 18x"37f3e", 18x"37bf6", 18x"378b2", 18x"37572", 18x"37236",




18x"36efe", 18x"36bca", 18x"3689a", 18x"36570", 18x"36248", 18x"35f26", 18x"35c06", 18x"358ea",




18x"355d4", 18x"352c0", 18x"34fb0", 18x"34ca4", 18x"3499c", 18x"34698", 18x"34398", 18x"3409c",




18x"33da2", 18x"33aac", 18x"337bc", 18x"334cc", 18x"331e2", 18x"32efc", 18x"32c18", 18x"32938",




18x"3265a", 18x"32382", 18x"320ac", 18x"31dd8", 18x"31b0a", 18x"3183e", 18x"31576", 18x"312b0",




18x"30fee", 18x"30d2e", 18x"30a74", 18x"307ba", 18x"30506", 18x"30254", 18x"2ffa4", 18x"2fcf8",




18x"2fa4e", 18x"2f7a8", 18x"2f506", 18x"2f266", 18x"2efca", 18x"2ed2e", 18x"2ea98", 18x"2e804",




18x"2e572", 18x"2e2e4", 18x"2e058", 18x"2ddce", 18x"2db48", 18x"2d8c6", 18x"2d646", 18x"2d3c8",




18x"2d14c", 18x"2ced4", 18x"2cc5e", 18x"2c9ea", 18x"2c77a", 18x"2c50c", 18x"2c2a2", 18x"2c038",




18x"2bdd2", 18x"2bb70", 18x"2b90e", 18x"2b6b0", 18x"2b454", 18x"2b1fa", 18x"2afa4", 18x"2ad4e",




18x"2aafc", 18x"2a8ac", 18x"2a660", 18x"2a414", 18x"2a1cc", 18x"29f86", 18x"29d42", 18x"29b00",




18x"298c2", 18x"29684", 18x"2944a", 18x"29210", 18x"28fda", 18x"28da6", 18x"28b74", 18x"28946",




18x"28718", 18x"284ec", 18x"282c4", 18x"2809c", 18x"27e78", 18x"27c56", 18x"27a34", 18x"27816",




18x"275fa", 18x"273e0", 18x"271c8", 18x"26fb0", 18x"26d9c", 18x"26b8a", 18x"2697a", 18x"2676c",




18x"26560", 18x"26356", 18x"2614c", 18x"25f46", 18x"25d42", 18x"25b40", 18x"2593e", 18x"25740",




18x"25542", 18x"25348", 18x"2514e", 18x"24f58", 18x"24d62", 18x"24b6e", 18x"2497c", 18x"2478c",




18x"2459e", 18x"243b0", 18x"241c6", 18x"23fde", 18x"23df6", 18x"23c10", 18x"23a2c", 18x"2384a",




18x"2366a", 18x"2348c", 18x"232ae", 18x"230d2", 18x"22efa", 18x"22d20", 18x"22b4a", 18x"22976",




18x"227a2", 18x"225d2", 18x"22402", 18x"22234", 18x"22066", 18x"21e9c", 18x"21cd2", 18x"21b0a",




18x"21944", 18x"2177e", 18x"215ba", 18x"213fa", 18x"21238", 18x"2107a", 18x"20ebc", 18x"20d00",




18x"20b46", 18x"2098e", 18x"207d6", 18x"20620", 18x"2046c", 18x"202b8", 18x"20108", 18x"1ff58",




18x"1fda8", 18x"1fbfc", 18x"1fa50", 18x"1f8a4", 18x"1f6fc", 18x"1f554", 18x"1f3ae", 18x"1f208",




18x"1f064", 18x"1eec2", 18x"1ed22", 18x"1eb82", 18x"1e9e4", 18x"1e846", 18x"1e6aa", 18x"1e510",




18x"1e378", 18x"1e1e0", 18x"1e04a", 18x"1deb4", 18x"1dd20", 18x"1db8e", 18x"1d9fc", 18x"1d86c",




18x"1d6de", 18x"1d550", 18x"1d3c4", 18x"1d238", 18x"1d0ae", 18x"1cf26", 18x"1cd9e", 18x"1cc18",




18x"1ca94", 18x"1c910", 18x"1c78c", 18x"1c60a", 18x"1c48a", 18x"1c30c", 18x"1c18e", 18x"1c010",




18x"1be94", 18x"1bd1a", 18x"1bba0", 18x"1ba28", 18x"1b8b2", 18x"1b73c", 18x"1b5c6", 18x"1b452",




18x"1b2e0", 18x"1b16e", 18x"1affe", 18x"1ae8e", 18x"1ad20", 18x"1abb4", 18x"1aa46", 18x"1a8dc",




 2.0 ... 2.9999




18x"1a772", 18x"1a608", 18x"1a4a0", 18x"1a33a", 18x"1a1d4", 18x"1a070", 18x"19f0c", 18x"19da8",




18x"19c48", 18x"19ae6", 18x"19986", 18x"19828", 18x"196ca", 18x"1956e", 18x"19412", 18x"192b8",




18x"1915e", 18x"19004", 18x"18eae", 18x"18d56", 18x"18c00", 18x"18aac", 18x"18958", 18x"18804",




18x"186b2", 18x"18562", 18x"18412", 18x"182c2", 18x"18174", 18x"18026", 18x"17eda", 18x"17d8e",




18x"17c44", 18x"17afa", 18x"179b2", 18x"1786a", 18x"17724", 18x"175de", 18x"17498", 18x"17354",




18x"17210", 18x"170ce", 18x"16f8c", 18x"16e4c", 18x"16d0c", 18x"16bcc", 18x"16a8e", 18x"16950",




18x"16814", 18x"166d8", 18x"1659e", 18x"16464", 18x"1632a", 18x"161f2", 18x"160ba", 18x"15f84",




18x"15e4e", 18x"15d1a", 18x"15be6", 18x"15ab2", 18x"15980", 18x"1584e", 18x"1571c", 18x"155ec",




18x"154bc", 18x"1538e", 18x"15260", 18x"15134", 18x"15006", 18x"14edc", 18x"14db0", 18x"14c86",




18x"14b5e", 18x"14a36", 18x"1490e", 18x"147e6", 18x"146c0", 18x"1459a", 18x"14476", 18x"14352",




18x"14230", 18x"1410c", 18x"13fea", 18x"13eca", 18x"13daa", 18x"13c8a", 18x"13b6c", 18x"13a4e",




18x"13930", 18x"13814", 18x"136f8", 18x"135dc", 18x"134c2", 18x"133a8", 18x"1328e", 18x"13176",




18x"1305e", 18x"12f48", 18x"12e30", 18x"12d1a", 18x"12c06", 18x"12af2", 18x"129de", 18x"128ca",




18x"127b8", 18x"126a6", 18x"12596", 18x"12486", 18x"12376", 18x"12266", 18x"12158", 18x"1204a",




18x"11f3e", 18x"11e32", 18x"11d26", 18x"11c1a", 18x"11b10", 18x"11a06", 18x"118fc", 18x"117f4",




18x"116ec", 18x"115e4", 18x"114de", 18x"113d8", 18x"112d2", 18x"111ce", 18x"110ca", 18x"10fc6",




18x"10ec2", 18x"10dc0", 18x"10cbe", 18x"10bbc", 18x"10abc", 18x"109bc", 18x"108bc", 18x"107be",




18x"106c0", 18x"105c2", 18x"104c4", 18x"103c8", 18x"102cc", 18x"101d0", 18x"100d6", 18x"0ffdc",




18x"0fee2", 18x"0fdea", 18x"0fcf0", 18x"0fbf8", 18x"0fb02", 18x"0fa0a", 18x"0f914", 18x"0f81e",




18x"0f72a", 18x"0f636", 18x"0f542", 18x"0f44e", 18x"0f35a", 18x"0f268", 18x"0f176", 18x"0f086",




18x"0ef94", 18x"0eea4", 18x"0edb4", 18x"0ecc6", 18x"0ebd6", 18x"0eae8", 18x"0e9fa", 18x"0e90e",




18x"0e822", 18x"0e736", 18x"0e64a", 18x"0e55e", 18x"0e474", 18x"0e38a", 18x"0e2a0", 18x"0e1b8",




18x"0e0d0", 18x"0dfe8", 18x"0df00", 18x"0de1a", 18x"0dd32", 18x"0dc4c", 18x"0db68", 18x"0da82",




18x"0d99e", 18x"0d8ba", 18x"0d7d6", 18x"0d6f4", 18x"0d612", 18x"0d530", 18x"0d44e", 18x"0d36c",




18x"0d28c", 18x"0d1ac", 18x"0d0cc", 18x"0cfee", 18x"0cf0e", 18x"0ce30", 18x"0cd54", 18x"0cc76",




18x"0cb9a", 18x"0cabc", 18x"0c9e0", 18x"0c906", 18x"0c82a", 18x"0c750", 18x"0c676", 18x"0c59c",




18x"0c4c4", 18x"0c3ea", 18x"0c312", 18x"0c23a", 18x"0c164", 18x"0c08c", 18x"0bfb6", 18x"0bee0",




18x"0be0a", 18x"0bd36", 18x"0bc62", 18x"0bb8c", 18x"0baba", 18x"0b9e6", 18x"0b912", 18x"0b840",




18x"0b76e", 18x"0b69c", 18x"0b5cc", 18x"0b4fa", 18x"0b42a", 18x"0b35a", 18x"0b28a", 18x"0b1bc",




18x"0b0ee", 18x"0b01e", 18x"0af50", 18x"0ae84", 18x"0adb6", 18x"0acea", 18x"0ac1e", 18x"0ab52",




18x"0aa86", 18x"0a9bc", 18x"0a8f0", 18x"0a826", 18x"0a75c", 18x"0a694", 18x"0a5ca", 18x"0a502",




18x"0a43a", 18x"0a372", 18x"0a2aa", 18x"0a1e4", 18x"0a11c", 18x"0a056", 18x"09f90", 18x"09ecc",




 3.0 ... 3.9999




18x"09e06", 18x"09d42", 18x"09c7e", 18x"09bba", 18x"09af6", 18x"09a32", 18x"09970", 18x"098ae",




18x"097ec", 18x"0972a", 18x"09668", 18x"095a8", 18x"094e8", 18x"09426", 18x"09368", 18x"092a8",




18x"091e8", 18x"0912a", 18x"0906c", 18x"08fae", 18x"08ef0", 18x"08e32", 18x"08d76", 18x"08cba",




18x"08bfe", 18x"08b42", 18x"08a86", 18x"089ca", 18x"08910", 18x"08856", 18x"0879c", 18x"086e2",




18x"08628", 18x"08570", 18x"084b6", 18x"083fe", 18x"08346", 18x"0828e", 18x"081d8", 18x"08120",




18x"0806a", 18x"07fb4", 18x"07efe", 18x"07e48", 18x"07d92", 18x"07cde", 18x"07c2a", 18x"07b76",




18x"07ac2", 18x"07a0e", 18x"0795a", 18x"078a8", 18x"077f4", 18x"07742", 18x"07690", 18x"075de",




18x"0752e", 18x"0747c", 18x"073cc", 18x"0731c", 18x"0726c", 18x"071bc", 18x"0710c", 18x"0705e",




18x"06fae", 18x"06f00", 18x"06e52", 18x"06da4", 18x"06cf6", 18x"06c4a", 18x"06b9c", 18x"06af0",




18x"06a44", 18x"06998", 18x"068ec", 18x"06840", 18x"06796", 18x"066ea", 18x"06640", 18x"06596",




18x"064ec", 18x"06442", 18x"0639a", 18x"062f0", 18x"06248", 18x"061a0", 18x"060f8", 18x"06050",




18x"05fa8", 18x"05f00", 18x"05e5a", 18x"05db4", 18x"05d0e", 18x"05c68", 18x"05bc2", 18x"05b1c",




18x"05a76", 18x"059d2", 18x"0592e", 18x"05888", 18x"057e4", 18x"05742", 18x"0569e", 18x"055fa",




18x"05558", 18x"054b6", 18x"05412", 18x"05370", 18x"052ce", 18x"0522e", 18x"0518c", 18x"050ec",




18x"0504a", 18x"04faa", 18x"04f0a", 18x"04e6a", 18x"04dca", 18x"04d2c", 18x"04c8c", 18x"04bee",




18x"04b50", 18x"04ab0", 18x"04a12", 18x"04976", 18x"048d8", 18x"0483a", 18x"0479e", 18x"04700",




18x"04664", 18x"045c8", 18x"0452c", 18x"04490", 18x"043f6", 18x"0435a", 18x"042c0", 18x"04226",




18x"0418a", 18x"040f0", 18x"04056", 18x"03fbe", 18x"03f24", 18x"03e8c", 18x"03df2", 18x"03d5a",




18x"03cc2", 18x"03c2a", 18x"03b92", 18x"03afa", 18x"03a62", 18x"039cc", 18x"03934", 18x"0389e",




18x"03808", 18x"03772", 18x"036dc", 18x"03646", 18x"035b2", 18x"0351c", 18x"03488", 18x"033f2",




18x"0335e", 18x"032ca", 18x"03236", 18x"031a2", 18x"03110", 18x"0307c", 18x"02fea", 18x"02f56",




18x"02ec4", 18x"02e32", 18x"02da0", 18x"02d0e", 18x"02c7c", 18x"02bec", 18x"02b5a", 18x"02aca",




18x"02a38", 18x"029a8", 18x"02918", 18x"02888", 18x"027f8", 18x"0276a", 18x"026da", 18x"0264a",




18x"025bc", 18x"0252e", 18x"024a0", 18x"02410", 18x"02384", 18x"022f6", 18x"02268", 18x"021da",




18x"0214e", 18x"020c0", 18x"02034", 18x"01fa8", 18x"01f1c", 18x"01e90", 18x"01e04", 18x"01d78",




18x"01cee", 18x"01c62", 18x"01bd8", 18x"01b4c", 18x"01ac2", 18x"01a38", 18x"019ae", 18x"01924",




18x"0189c", 18x"01812", 18x"01788", 18x"01700", 18x"01676", 18x"015ee", 18x"01566", 18x"014de",




18x"01456", 18x"013ce", 18x"01346", 18x"012c0", 18x"01238", 18x"011b2", 18x"0112c", 18x"010a4",




18x"0101e", 18x"00f98", 18x"00f12", 18x"00e8c", 18x"00e08", 18x"00d82", 18x"00cfe", 18x"00c78",




18x"00bf4", 18x"00b70", 18x"00aec", 18x"00a68", 18x"009e4", 18x"00960", 18x"008dc", 18x"00858",




18x"007d6", 18x"00752", 18x"006d0", 18x"0064e", 18x"005cc", 18x"0054a", 18x"004c8", 18x"00446",




18x"003c4", 18x"00342", 18x"002c2", 18x"00240", 18x"001c0", 18x"00140", 18x"000c0", 18x"00040"




);





FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



 Left and right shifter with 120 bit input and 64 bit output.




 Shifts inp left by shift bits and returns the upper 64 bits of




 the result. The shift parameter is interpreted as a signed




 number in the range 64..63, with negative values indicating




 right shifts.




function shifter_64(inp: std_ulogic_vector(119 downto 0);




shift: std_ulogic_vector(6 downto 0))




return std_ulogic_vector is




variable s1 : std_ulogic_vector(94 downto 0);




variable s2 : std_ulogic_vector(70 downto 0);




variable shift_result : std_ulogic_vector(63 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



begin




case shift(6 downto 5) is




when "00" =>




s1 := inp(119 downto 25);




when "01" =>




s1 := inp(87 downto 0) & "0000000";




when "10" =>




s1 := x"0000000000000000" & inp(119 downto 89);




when others =>




s1 := x"00000000" & inp(119 downto 57);




end case;




case shift(4 downto 3) is




when "00" =>




s2 := s1(94 downto 24);




when "01" =>




s2 := s1(86 downto 16);




when "10" =>




s2 := s1(78 downto 8);




when others =>




s2 := s1(70 downto 0);




end case;




case shift(2 downto 0) is




when "000" =>




shift_result := s2(70 downto 7);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



when "001" =>




shift_result := s2(69 downto 6);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



when "010" =>




shift_result := s2(68 downto 5);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



when "011" =>




shift_result := s2(67 downto 4);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



when "100" =>




shift_result := s2(66 downto 3);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



when "101" =>




shift_result := s2(65 downto 2);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



when "110" =>




shift_result := s2(64 downto 1);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



when others =>




shift_result := s2(63 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



end case;




return shift_result;

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



end;








 Generate a mask with 0bits on the left and 1bits on the right which




 selects the bits will be lost in doing a right shift. The shift




 parameter is the bottom 6 bits of a negative shift count,




 indicating a right shift.




function right_mask(shift: unsigned(5 downto 0)) return std_ulogic_vector is




variable mask_result: std_ulogic_vector(63 downto 0);

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



begin




mask_result := (others => '0');




if is_X(shift) then




mask_result := (others => 'X');




return mask_result;




end if;

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



for i in 0 to 63 loop




if i >= shift then




mask_result(63  i) := '1';

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



end if;




end loop;




return mask_result;

FPU: Implement floating convert from integer instructions
This implements fcfid, fcfidu, fcfids and fcfidus, which convert
64bit integer values in an FPR into a floatingpoint value.
This brings in a lot of the datapath that will be needed in
future, including the shifter, adder, mask generator and
countleadingzeroes logic, along with the machinery for rounding
to singleprecision or doubleprecision, detecting inexact results,
signalling inexactresult exceptions, and updating result flags
in the FPSCR.
Signedoffby: Paul Mackerras <paulus@ozlabs.org>
4 years ago



end;








 Split a DP floatingpoint number into components and work out its class.




 If is_int = 1, the input is considered an integer




function decode_dp(fpr: std_ulogic_vector(63 downto 0); is_fp: std_ulogic;




is_32bint: std_ulogic; is_signed: std_ulogic) return fpu_reg_type is




variable reg : fpu_reg_type;




variable exp_nz : std_ulogic;




variable exp_ao : std_ulogic;




variable frac_nz : std_ulogic;




variable low_nz : std_ulogic;




variable cls : std_ulogic_vector(2 downto 0);




begin




reg.negative := fpr(63);




reg.denorm := '0';




exp_nz := or (fpr(62 downto 52));




exp_ao := and (fpr(62 downto 52));




frac_nz := or (fpr(51 downto 0));




low_nz := or (fpr(31 downto 0));




if is_fp = '1' then




reg.denorm := frac_nz and not exp_nz;




reg.exponent := signed(resize(unsigned(fpr(62 downto 52)), EXP_BITS))  to_signed(1023, EXP_BITS);




if exp_nz = '0' then




reg.exponent := to_signed(1022, EXP_BITS);




end if;




reg.mantissa := std_ulogic_vector(shift_left(resize(unsigned(exp_nz & fpr(51 downto 0)), 64),




UNIT_BIT  52));




cls := exp_ao & exp_nz & frac_nz;




case cls is




when "000" => reg.class := ZERO;




when "001" => reg.class := FINITE;  denormalized




when "010" => reg.class := FINITE;




when "011" => reg.class := FINITE;




when "110" => reg.class := INFINITY;




when others => reg.class := NAN;




end case;




elsif is_32bint = '1' then




reg.negative := fpr(31);




reg.mantissa(31 downto 0) := fpr(31 downto 0);



