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105 lines
3.2 KiB
Python
105 lines
3.2 KiB
Python
from amaranth import *
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from power_fv import pfv
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from power_fv.insn.const import *
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from . import InsnSpec
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from .utils import iea
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__all__ = ["CompareSpec"]
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class CompareSpec(InsnSpec, Elaboratable):
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def __init__(self, insn):
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self.pfv = pfv.Interface()
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self.insn = insn
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def elaborate(self, platform):
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m = Module()
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m.d.comb += [
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self.pfv.stb .eq(1),
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self.pfv.insn.eq(Cat(Const(0, 32), self.insn.as_value())),
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self.pfv.intr.eq(0),
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self.pfv.nia .eq(iea(self.pfv.cia + 4, self.pfv.msr.r_data.sf)),
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self.pfv.msr.r_mask.sf.eq(1),
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self.pfv.xer.r_mask.so.eq(1),
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]
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src_a = Signal(64)
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src_b = Signal(64)
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result = Record([
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("lt", 1),
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("gt", 1),
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("eq_", 1),
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("so", 1),
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])
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# Operand A : (RA) or [(RA)(32:63) sign-extended or zero-extended]
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m.d.comb += [
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self.pfv.ra.index.eq(self.insn.RA),
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self.pfv.ra.r_stb.eq(1),
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]
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if isinstance(self.insn, (CMPI, CMP)):
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with m.If(self.insn.L):
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m.d.comb += src_a.eq(self.pfv.ra.r_data)
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with m.Else():
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m.d.comb += src_a.eq(self.pfv.ra.r_data[:32].as_signed())
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elif isinstance(self.insn, (CMPL, CMPLI)):
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with m.If(self.insn.L):
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m.d.comb += src_a.eq(self.pfv.ra.r_data)
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with m.Else():
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m.d.comb += src_a.eq(self.pfv.ra.r_data[:32].as_unsigned())
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else:
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assert False
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# Operand B : SI or UI or (RB) or [(RB)(32:63) sign-extended or zero-extended]
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if isinstance(self.insn, (CMP, CMPL)):
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m.d.comb += [
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self.pfv.rb.index.eq(self.insn.RB),
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self.pfv.rb.r_stb.eq(1),
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]
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if isinstance(self.insn, CMPI):
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m.d.comb += src_b.eq(self.insn.SI)
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elif isinstance(self.insn, CMPLI):
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m.d.comb += src_b.eq(self.insn.UI)
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elif isinstance(self.insn, CMP):
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with m.If(self.insn.L):
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m.d.comb += src_b.eq(self.pfv.rb.r_data)
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with m.Else():
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m.d.comb += src_b.eq(self.pfv.rb.r_data[:32].as_signed())
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elif isinstance(self.insn, CMPL):
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with m.If(self.insn.L):
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m.d.comb += src_b.eq(self.pfv.rb.r_data)
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with m.Else():
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m.d.comb += src_b.eq(self.pfv.rb.r_data[:32].as_unsigned())
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else:
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assert False
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# Result
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if isinstance(self.insn, (CMPI, CMP)):
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m.d.comb += result.lt.eq(src_a.as_signed() < src_b.as_signed())
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elif isinstance(self.insn, (CMPLI, CMPL)):
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m.d.comb += result.lt.eq(src_a.as_unsigned() < src_b.as_unsigned())
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else:
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assert False
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m.d.comb += [
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result.gt .eq(~(result.lt | result.eq_)),
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result.eq_.eq(src_a == src_b),
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result.so .eq(self.pfv.xer.r_data.so),
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]
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m.d.comb += [
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self.pfv.cr.w_mask[::-1].word_select(self.insn.BF, width=4).eq(0b1111),
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self.pfv.cr.w_data[::-1].word_select(self.insn.BF, width=4).eq(result),
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]
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return m
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