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predecode: Add more comments to row_predecode_rom and insn_code values

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This adds comments to row_predecode_rom to aid understanding how the
columns in the second half of the table are allocated to different
primary opcodes, and to the insn_code values to assist in locating the
code with a given numeric value.  No code change.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
pull/382/head
Paul Mackerras 2 years ago
parent 6db626d245
commit 58e799b350
2 changed files with 35 additions and 31 deletions
Show Stats Download Patch File Download Diff File

58
decode_types.vhdl
Unescape Escape View File

@ -32,7 +32,7 @@ package decode_types is
-- comparisons of the insn_code for the instruction with a few constants. -- comparisons of the insn_code for the instruction with a few constants.
type insn_code is ( type insn_code is (
-- The following instructions don't have an RB operand or access FPRs -- The following instructions don't have an RB operand or access FPRs
INSN_illegal, INSN_illegal, -- 0
INSN_fetch_fail, INSN_fetch_fail,
INSN_addi, INSN_addi,
INSN_addic, INSN_addic,
@ -42,7 +42,7 @@ package decode_types is
INSN_addpcis, INSN_addpcis,
INSN_addze, INSN_addze,
INSN_andi_dot, INSN_andi_dot,
INSN_andis_dot, INSN_andis_dot, -- 10
INSN_attn, INSN_attn,
INSN_b, INSN_b,
INSN_bc, INSN_bc,
@ -52,7 +52,7 @@ package decode_types is
INSN_cbcdtd, INSN_cbcdtd,
INSN_cdtbcd, INSN_cdtbcd,
INSN_cmpi, INSN_cmpi,
INSN_cmpli, INSN_cmpli, -- 20
INSN_cntlzw, INSN_cntlzw,
INSN_cntlzd, INSN_cntlzd,
INSN_cnttzw, INSN_cnttzw,
@ -62,7 +62,7 @@ package decode_types is
INSN_creqv, INSN_creqv,
INSN_crnand, INSN_crnand,
INSN_crnor, INSN_crnor,
INSN_cror, INSN_cror, -- 30
INSN_crorc, INSN_crorc,
INSN_crxor, INSN_crxor,
INSN_darn, INSN_darn,
@ -72,7 +72,7 @@ package decode_types is
INSN_extsw, INSN_extsw,
INSN_extswsli, INSN_extswsli,
INSN_isync, INSN_isync,
INSN_lbz, INSN_lbz, -- 40
INSN_lbzu, INSN_lbzu,
INSN_ld, INSN_ld,
INSN_ldu, INSN_ldu,
@ -82,7 +82,7 @@ package decode_types is
INSN_lhzu, INSN_lhzu,
INSN_lwa, INSN_lwa,
INSN_lwz, INSN_lwz,
INSN_lwzu, INSN_lwzu, -- 50
INSN_mcrf, INSN_mcrf,
INSN_mcrfs, INSN_mcrfs,
INSN_mcrxrx, INSN_mcrxrx,
@ -92,7 +92,7 @@ package decode_types is
INSN_mtcrf, INSN_mtcrf,
INSN_mtfsb, INSN_mtfsb,
INSN_mtfsfi, INSN_mtfsfi,
INSN_mtmsr, INSN_mtmsr, -- 60
INSN_mtmsrd, INSN_mtmsrd,
INSN_mtspr, INSN_mtspr,
INSN_mulli, INSN_mulli,
@ -102,7 +102,7 @@ package decode_types is
INSN_oris, INSN_oris,
INSN_popcntb, INSN_popcntb,
INSN_popcntw, INSN_popcntw,
INSN_popcntd, INSN_popcntd, -- 70
INSN_prtyw, INSN_prtyw,
INSN_prtyd, INSN_prtyd,
INSN_rfid, INSN_rfid,
@ -112,7 +112,7 @@ package decode_types is
INSN_rldimi, INSN_rldimi,
INSN_rlwimi, INSN_rlwimi,
INSN_rlwinm, INSN_rlwinm,
INSN_sc, INSN_sc, -- 80
INSN_setb, INSN_setb,
INSN_slbia, INSN_slbia,
INSN_sradi, INSN_sradi,
@ -122,7 +122,7 @@ package decode_types is
INSN_std, INSN_std,
INSN_stdu, INSN_stdu,
INSN_sth, INSN_sth,
INSN_sthu, INSN_sthu, -- 90
INSN_stw, INSN_stw,
INSN_stwu, INSN_stwu,
INSN_subfic, INSN_subfic,
@ -132,7 +132,7 @@ package decode_types is
INSN_tdi, INSN_tdi,
INSN_tlbsync, INSN_tlbsync,
INSN_twi, INSN_twi,
INSN_wait, INSN_wait, -- 100
INSN_xori, INSN_xori,
INSN_xoris, INSN_xoris,


@ -150,7 +150,7 @@ package decode_types is
INSN_and, INSN_and,
INSN_andc, INSN_andc,
INSN_bperm, INSN_bperm,
INSN_cmp, INSN_cmp, -- 120
INSN_cmpb, INSN_cmpb,
INSN_cmpeqb, INSN_cmpeqb,
INSN_cmpl, INSN_cmpl,
@ -160,7 +160,7 @@ package decode_types is
INSN_dcbt, INSN_dcbt,
INSN_dcbtst, INSN_dcbtst,
INSN_dcbz, INSN_dcbz,
INSN_divd, INSN_divd, -- 130
INSN_divdu, INSN_divdu,
INSN_divde, INSN_divde,
INSN_divdeu, INSN_divdeu,
@ -170,7 +170,7 @@ package decode_types is
INSN_divweu, INSN_divweu,
INSN_eqv, INSN_eqv,
INSN_icbi, INSN_icbi,
INSN_icbt, INSN_icbt, -- 140
INSN_isel, INSN_isel,
INSN_lbarx, INSN_lbarx,
INSN_lbzcix, INSN_lbzcix,
@ -180,7 +180,7 @@ package decode_types is
INSN_ldbrx, INSN_ldbrx,
INSN_ldcix, INSN_ldcix,
INSN_ldx, INSN_ldx,
INSN_ldux, INSN_ldux, -- 150
INSN_lharx, INSN_lharx,
INSN_lhax, INSN_lhax,
INSN_lhaux, INSN_lhaux,
@ -190,7 +190,7 @@ package decode_types is
INSN_lhzux, INSN_lhzux,
INSN_lwarx, INSN_lwarx,
INSN_lwax, INSN_lwax,
INSN_lwaux, INSN_lwaux, -- 160
INSN_lwbrx, INSN_lwbrx,
INSN_lwzcix, INSN_lwzcix,
INSN_lwzx, INSN_lwzx,
@ -200,7 +200,7 @@ package decode_types is
INSN_moduw, INSN_moduw,
INSN_modud, INSN_modud,
INSN_mulhw, INSN_mulhw,
INSN_mulhwu, INSN_mulhwu, -- 170
INSN_mulhd, INSN_mulhd,
INSN_mulhdu, INSN_mulhdu,
INSN_mullw, INSN_mullw,
@ -210,7 +210,7 @@ package decode_types is
INSN_or, INSN_or,
INSN_orc, INSN_orc,
INSN_rldcl, INSN_rldcl,
INSN_rldcr, INSN_rldcr, -- 180
INSN_rlwnm, INSN_rlwnm,
INSN_slw, INSN_slw,
INSN_sld, INSN_sld,
@ -220,7 +220,7 @@ package decode_types is
INSN_srd, INSN_srd,
INSN_stbcix, INSN_stbcix,
INSN_stbcx, INSN_stbcx,
INSN_stbx, INSN_stbx, -- 190
INSN_stbux, INSN_stbux,
INSN_stdbrx, INSN_stdbrx,
INSN_stdcix, INSN_stdcix,
@ -230,7 +230,7 @@ package decode_types is
INSN_sthbrx, INSN_sthbrx,
INSN_sthcix, INSN_sthcix,
INSN_sthcx, INSN_sthcx,
INSN_sthx, INSN_sthx, -- 200
INSN_sthux, INSN_sthux,
INSN_stwbrx, INSN_stwbrx,
INSN_stwcix, INSN_stwcix,
@ -240,7 +240,7 @@ package decode_types is
INSN_subf, INSN_subf,
INSN_subfc, INSN_subfc,
INSN_subfe, INSN_subfe,
INSN_td, INSN_td, -- 210
INSN_tlbie, INSN_tlbie,
INSN_tlbiel, INSN_tlbiel,
INSN_tw, INSN_tw,
@ -272,7 +272,7 @@ package decode_types is
INSN_stfdu, INSN_stfdu,
INSN_stfs, INSN_stfs,
INSN_stfsu, INSN_stfsu,
INSN_stfdux, INSN_stfdux, -- 260
INSN_stfdx, INSN_stfdx,
INSN_stfiwx, INSN_stfiwx,
INSN_stfsux, INSN_stfsux,
@ -284,7 +284,7 @@ package decode_types is
INSN_lfs, INSN_lfs,
INSN_lfsu, INSN_lfsu,
INSN_lfdx, INSN_lfdx,
INSN_lfdux, INSN_lfdux, -- 270
INSN_lfiwax, INSN_lfiwax,
INSN_lfiwzx, INSN_lfiwzx,
INSN_lfsx, INSN_lfsx,
@ -296,7 +296,7 @@ package decode_types is
INSN_fadd, INSN_fadd,
INSN_fadds, INSN_fadds,
INSN_fcfid, INSN_fcfid,
INSN_fcfids, INSN_fcfids, -- 280
INSN_fcfidu, INSN_fcfidu,
INSN_fcfidus, INSN_fcfidus,
INSN_fcmpo, INSN_fcmpo,
@ -306,7 +306,7 @@ package decode_types is
INSN_fctidz, INSN_fctidz,
INSN_fctidu, INSN_fctidu,
INSN_fctiduz, INSN_fctiduz,
INSN_fctiw, INSN_fctiw, -- 290
INSN_fctiwz, INSN_fctiwz,
INSN_fctiwu, INSN_fctiwu,
INSN_fctiwuz, INSN_fctiwuz,
@ -316,7 +316,7 @@ package decode_types is
INSN_fmrgew, INSN_fmrgew,
INSN_fmrgow, INSN_fmrgow,
INSN_fnabs, INSN_fnabs,
INSN_fneg, INSN_fneg, -- 300
INSN_fre, INSN_fre,
INSN_fres, INSN_fres,
INSN_frim, INSN_frim,
@ -326,7 +326,7 @@ package decode_types is
INSN_frsp, INSN_frsp,
INSN_frsqrte, INSN_frsqrte,
INSN_frsqrtes, INSN_frsqrtes,
INSN_fsqrt, INSN_fsqrt, -- 310
INSN_fsqrts, INSN_fsqrts,
INSN_fsub, INSN_fsub,
INSN_fsubs, INSN_fsubs,
@ -339,7 +339,7 @@ package decode_types is
INSN_318, INSN_319, INSN_318, INSN_319,


-- The following instructions access FRA, FRB (possibly) and FRC operands -- The following instructions access FRA, FRB (possibly) and FRC operands
INSN_fmul, INSN_fmul, -- 320
INSN_fmuls, INSN_fmuls,
INSN_fmadd, INSN_fmadd,
INSN_fmadds, INSN_fmadds,
@ -349,7 +349,7 @@ package decode_types is
INSN_fnmadds, INSN_fnmadds,
INSN_fnmsub, INSN_fnmsub,
INSN_fnmsubs, INSN_fnmsubs,
INSN_fsel INSN_fsel -- 330
); );


constant INSN_first_rb : insn_code := INSN_add; constant INSN_first_rb : insn_code := INSN_add;

8
predecode.vhdl
Unescape Escape View File

@ -389,6 +389,8 @@ architecture behaviour of predecoder is
-- fit into 2048 entries, the columns are remapped so that 16-24 are -- fit into 2048 entries, the columns are remapped so that 16-24 are
-- stored here as 8-15; in other words the address bits are -- stored here as 8-15; in other words the address bits are
-- 1, insn(10..6), 1, insn(5), insn(3..1) -- 1, insn(10..6), 1, insn(5), insn(3..1)
-- Columns 16-17 here are opcode 19 columns 0-1
-- Columns 24-31 here are opcode 19 columns 16-23
2#1_10000_11000# => INSN_bcctr, 2#1_10000_11000# => INSN_bcctr,
2#1_00000_11000# => INSN_bclr, 2#1_00000_11000# => INSN_bclr,
2#1_10001_11000# => INSN_bctar, 2#1_10001_11000# => INSN_bctar,
@ -405,15 +407,17 @@ architecture behaviour of predecoder is
2#1_00000_11010# => INSN_rfid, 2#1_00000_11010# => INSN_rfid,


-- Major opcode 59 -- Major opcode 59
-- Address bits are 1, insn(10..6), 1, 0, insn(3..1)
-- Only column 14 is valid here; columns 16-31 are handled in the major table -- Only column 14 is valid here; columns 16-31 are handled in the major table
-- Column 14 is mapped to column 6 of the space which is -- Column 14 is mapped to column 22.
-- mostly used for opcode 19. -- Columns 20-23 here are opcode 59 columns 12-15
2#1_11010_10110# => INSN_fcfids, 2#1_11010_10110# => INSN_fcfids,
2#1_11110_10110# => INSN_fcfidus, 2#1_11110_10110# => INSN_fcfidus,


-- Major opcode 63 -- Major opcode 63
-- Columns 0-15 are mapped here; columns 16-31 are in the major table. -- Columns 0-15 are mapped here; columns 16-31 are in the major table.
-- Address bits are 1, insn(10:6), 0, insn(4:1) -- Address bits are 1, insn(10:6), 0, insn(4:1)
-- Columns 0-15 here are opcode 63 columns 0-15
2#1_00000_00000# => INSN_fcmpu, 2#1_00000_00000# => INSN_fcmpu,
2#1_00001_00000# => INSN_fcmpo, 2#1_00001_00000# => INSN_fcmpo,
2#1_00010_00000# => INSN_mcrfs, 2#1_00010_00000# => INSN_mcrfs,

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