From 43de8ed4528ea7627cfe2cbac9374074b22687ae Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Sat, 17 Aug 2019 11:32:15 +0100 Subject: [PATCH] simplify sign/term bits using Cat --- src/ieee754/part_mul_add/multiply.py | 40 +++++++++++++++------------- 1 file changed, 22 insertions(+), 18 deletions(-) diff --git a/src/ieee754/part_mul_add/multiply.py b/src/ieee754/part_mul_add/multiply.py index 3695f22c..aef8b918 100644 --- a/src/ieee754/part_mul_add/multiply.py +++ b/src/ieee754/part_mul_add/multiply.py @@ -608,6 +608,7 @@ class Mul8_16_32_64(Elaboratable): ]: byte_width = 8 // len(parts) bit_width = 8 * byte_width + nat, nbt, nla, nlb = [], [], [], [] for i in range(len(parts)): be = parts[i] & self.a[(i + 1) * bit_width - 1] \ & self._a_signed[i * byte_width] @@ -621,24 +622,27 @@ class Mul8_16_32_64(Elaboratable): # for 8-bit values: form a * 0xFF00 by using -a * 0x100, the # negation operation is split into a bitwise not and a +1. # likewise for 16, 32, and 64-bit values. - m.d.comb += [ - not_a_term.bit_select(bit_width * 2 * i, bit_width * 2) - .eq(Mux(a_enabled, - Cat(Repl(0, bit_width), - ~self.a.bit_select(bit_width * i, bit_width)), - 0)), - - neg_lsb_a_term.bit_select(bit_width * 2 * i, bit_width * 2) - .eq(Cat(Repl(0, bit_width), a_enabled)), - - not_b_term.bit_select(bit_width * 2 * i, bit_width * 2) - .eq(Mux(b_enabled, - Cat(Repl(0, bit_width), - ~self.b.bit_select(bit_width * i, bit_width)), - 0)), - - neg_lsb_b_term.bit_select(bit_width * 2 * i, bit_width * 2) - .eq(Cat(Repl(0, bit_width), b_enabled))] + nat.append(Mux(a_enabled, + Cat(Repl(0, bit_width), + ~self.a.bit_select(bit_width * i, bit_width)), + 0)) + + nla.append(Cat(Repl(0, bit_width), a_enabled, + Repl(0, bit_width-1))) + + nbt.append(Mux(b_enabled, + Cat(Repl(0, bit_width), + ~self.b.bit_select(bit_width * i, bit_width)), + 0)) + + nlb.append(Cat(Repl(0, bit_width), b_enabled, + Repl(0, bit_width-1))) + + m.d.comb += [not_a_term.eq(Cat(*nat)), + not_b_term.eq(Cat(*nbt)), + neg_lsb_a_term.eq(Cat(*nla)), + neg_lsb_b_term.eq(Cat(*nlb)), + ] expanded_part_pts = PartitionPoints() for i, v in self.part_pts.items(): -- 2.30.2