From b83e8f2f6b9cbe3320e9d6e46d5f7b328037dc88 Mon Sep 17 00:00:00 2001 From: Konstantinos Margaritis Date: Sun, 30 Apr 2023 21:29:47 +0000 Subject: [PATCH] Handle large 64-bit values, but only the low 64-bit half of the multiplication, add more tests --- openpower/isa/butterfly.mdwn | 39 +++++++++----------- src/openpower/test/alu/maddsubrs_cases.py | 45 +++++++++++++++++++++++ 2 files changed, 63 insertions(+), 21 deletions(-) diff --git a/openpower/isa/butterfly.mdwn b/openpower/isa/butterfly.mdwn index 1446af11..65f4dc56 100644 --- a/openpower/isa/butterfly.mdwn +++ b/openpower/isa/butterfly.mdwn @@ -13,32 +13,29 @@ Pseudo-code: n <- SH sum <- (RT) + (RA) diff <- (RT) - (RA) - prod1 <- MULS(RB, sum)[XLEN:(XLEN*2)-1] - prod2 <- MULS(RB, diff)[XLEN:(XLEN*2)-1] + prod1 <- MULS(RB, sum) + prod1_lo <- prod1[XLEN:(XLEN*2)-1] + prod2 <- MULS(RB, diff) + prod2_lo <- prod2[XLEN:(XLEN*2)-1] if n = 0 then - #round <- EXTS([0]*(XLEN-1) || [1]*1) - #prod1 <- ROTL64(prod1, 1) - #prod2 <- ROTL64(prod2, 1) - #prod1 <- prod1 + round - #prod2 <- prod2 + round - #res1 <- ROTL64(prod1, XLEN-1) - #res2 <- ROTL64(prod2, XLEN-1) - #m <- MASK(1, (XLEN-1)) - RT <- prod1 - RS <- prod2 + RT <- prod1_lo + RS <- prod2_lo else - round <- EXTS([0]*(XLEN -n -1) || [1]*1 || [0]*(n-1)) - prod1 <- prod1 + round - prod2 <- prod2 + round - res1 <- ROTL64(prod1, XLEN-n) - res2 <- ROTL64(prod2, XLEN-n) + if n = 1 then + round <- [0]*(XLEN -n) || [1]*1 + else + round <- [0]*(XLEN -n) || [1]*1 || [0]*(n-1) + prod1_lo <- prod1_lo + round + prod2_lo <- prod2_lo + round m <- MASK(n, (XLEN-1)) - signbit1 <- prod1[0] - signbit2 <- prod2[0] + res1 <- ROTL64(prod1_lo, XLEN-n) & m + res2 <- ROTL64(prod2_lo, XLEN-n) & m + signbit1 <- prod1_lo[0] + signbit2 <- prod2_lo[0] smask1 <- ([signbit1]*XLEN) & ¬m smask2 <- ([signbit2]*XLEN) & ¬m - RT <- (res1 & m | smask1) - RS <- (res2 & m | smask2) + RT <- (res1 | smask1) + RS <- (res2 | smask2) Special Registers Altered: diff --git a/src/openpower/test/alu/maddsubrs_cases.py b/src/openpower/test/alu/maddsubrs_cases.py index 56b61f82..2a495f60 100644 --- a/src/openpower/test/alu/maddsubrs_cases.py +++ b/src/openpower/test/alu/maddsubrs_cases.py @@ -41,3 +41,48 @@ class MADDSUBRSTestCase(TestAccumulatorBase): e.intregs[2] = 0xffffffffd90f96f9 e.intregs[3] = 0x00002d41 self.add_case(Program(lst, bigendian), initial_regs, expected=e) + + def case_2_maddsubrs(self): + isa = SVP64Asm(["maddsubrs 1,2,2,3"]) + lst = list(isa) + + initial_regs = [0] * 32 + initial_regs[1] = 0x100000000 + initial_regs[2] = 0x000000003 + initial_regs[3] = 0x10000000 + + e = ExpectedState(pc=4) + e.intregs[1] = 0x40000000c000000; + e.intregs[2] = 0x3fffffff4000000; + e.intregs[3] = 0x10000000; + self.add_case(Program(lst, bigendian), initial_regs, expected=e) + + def case_3_maddsubrs(self): + isa = SVP64Asm(["maddsubrs 1,2,16,3"]) + lst = list(isa) + + initial_regs = [0] * 32 + initial_regs[1] = 0x100000000 + initial_regs[2] = 0x000000003 + initial_regs[3] = 0x10000000 + + e = ExpectedState(pc=4) + e.intregs[1] = 0x100000003000; + e.intregs[2] = 0x0fffffffd000; + e.intregs[3] = 0x10000000; + self.add_case(Program(lst, bigendian), initial_regs, expected=e) + + def case_3_maddsubrs(self): + isa = SVP64Asm(["maddsubrs 1,2,1,3"]) + lst = list(isa) + + initial_regs = [0] * 32 + initial_regs[1] = 0x100000000 + initial_regs[2] = 0x000000003 + initial_regs[3] = 0xff0000000 + + e = ExpectedState(pc=4) + e.intregs[1] = 0xf8000017e8000000; + e.intregs[2] = 0xf7ffffe818000000; + e.intregs[3] = 0xff0000000; + self.add_case(Program(lst, bigendian), initial_regs, expected=e) -- 2.30.2