# check negate: select signed/unsigned
mul_o = Signal(o_i.width, reset_less=True)
comb += mul_o.eq(Mux(self.i.neg_res, -o_i, o_i))
- comb += o.ok.eq(1)
# OP_MUL_nnn - select hi32/hi64/lo64 from result
with m.Switch(op.insn_type):
# hi-32 replicated twice
with m.Case(MicrOp.OP_MUL_H32):
comb += o.data.eq(Repl(mul_o[32:64], 2))
+ comb += o.ok.eq(1)
# hi-64
with m.Case(MicrOp.OP_MUL_H64):
comb += o.data.eq(mul_o[64:128])
+ comb += o.ok.eq(1)
# lo-64 - overflow
- with m.Default():
+ with m.Case(MicrOp.OP_MUL_L64):
# take the low 64 bits of the mul
comb += o.data.eq(mul_o[0:64])
+ comb += o.ok.eq(1)
- # compute overflow
+ # compute overflow 32/64
mul_ov = Signal(reset_less=True)
with m.If(is_32bit):
- m32 = mul_o[31:64] # yes really bits 31 to 63 (incl)
- comb += mul_ov.eq(m32.bool() & ~m32.all())
+ # here we're checking that the top 32 bits is the
+ # sign-extended version of the bottom 32 bits.
+ m31 = mul_o[31:64] # yes really bits 31 to 63 (incl)
+ comb += mul_ov.eq(m31.bool() & ~m31.all())
with m.Else():
- m64 = mul_o[63:128] # yes really bits 63 to 127 (incl)
- comb += mul_ov.eq(m64.bool() & ~m64.all())
+ # here we're checking that the top 64 bits is the
+ # sign-extended version of the bottom 64 bits.
+ m63 = mul_o[63:128] # yes really bits 63 to 127 (incl)
+ comb += mul_ov.eq(m63.bool() & ~m63.all())
# 32-bit (ov[1]) and 64-bit (ov[0]) overflow - both same
comb += ov_o.data.eq(Repl(mul_ov, 2)) # sets OV _and_ OV32
###### sticky overflow and context, both pass-through #####
- comb += self.o.xer_so.data.eq(self.i.xer_so)
+ comb += self.o.xer_so.eq(self.i.xer_so)
comb += self.o.ctx.eq(self.i.ctx)
return m