From 1419d0e92511735adb319b310155a1965dc20eb8 Mon Sep 17 00:00:00 2001 From: Joel Sing Date: Thu, 27 Jun 2024 20:02:04 +1000 Subject: [PATCH] math/big: implement subVV in riscv64 assembly MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This provides an assembly implementation of subVV for riscv64, processing up to four words per loop, resulting in a significant performance gain. On a StarFive VisionFive 2: │ subvv.1 │ subvv.2 │ │ sec/op │ sec/op vs base │ SubVV/1-4 73.46n ± 0% 48.08n ± 0% -34.55% (p=0.000 n=10) SubVV/2-4 88.13n ± 0% 58.76n ± 0% -33.33% (p=0.000 n=10) SubVV/3-4 102.80n ± 0% 69.45n ± 0% -32.44% (p=0.000 n=10) SubVV/4-4 117.50n ± 0% 72.11n ± 0% -38.63% (p=0.000 n=10) SubVV/5-4 132.20n ± 0% 82.80n ± 0% -37.37% (p=0.000 n=10) SubVV/10-4 216.3n ± 0% 126.9n ± 0% -41.33% (p=0.000 n=10) SubVV/100-4 1659.0n ± 0% 886.5n ± 0% -46.56% (p=0.000 n=10) SubVV/1000-4 16.089µ ± 0% 8.401µ ± 0% -47.78% (p=0.000 n=10) SubVV/10000-4 244.7µ ± 0% 176.8µ ± 0% -27.74% (p=0.000 n=10) SubVV/100000-4 2.562m ± 0% 1.871m ± 0% -26.96% (p=0.000 n=10) geomean 1.436µ 904.4n -37.04% │ subvv.1 │ subvv.2 │ │ B/s │ B/s vs base │ SubVV/1-4 830.9Mi ± 0% 1269.5Mi ± 0% +52.79% (p=0.000 n=10) SubVV/2-4 1.353Gi ± 0% 2.029Gi ± 0% +49.99% (p=0.000 n=10) SubVV/3-4 1.739Gi ± 0% 2.575Gi ± 0% +48.06% (p=0.000 n=10) SubVV/4-4 2.029Gi ± 0% 3.306Gi ± 0% +62.96% (p=0.000 n=10) SubVV/5-4 2.254Gi ± 0% 3.600Gi ± 0% +59.67% (p=0.000 n=10) SubVV/10-4 2.755Gi ± 0% 4.699Gi ± 0% +70.53% (p=0.000 n=10) SubVV/100-4 3.594Gi ± 0% 6.723Gi ± 0% +87.08% (p=0.000 n=10) SubVV/1000-4 3.705Gi ± 0% 7.095Gi ± 0% +91.52% (p=0.000 n=10) SubVV/10000-4 2.436Gi ± 0% 3.372Gi ± 0% +38.39% (p=0.000 n=10) SubVV/100000-4 2.327Gi ± 0% 3.185Gi ± 0% +36.91% (p=0.000 n=10) geomean 2.118Gi 3.364Gi +58.84% Change-Id: I361cb3f4195b27a9f1e9486c9e1fdbeaa94d32b4 Reviewed-on: https://go-review.googlesource.com/c/go/+/595396 LUCI-TryBot-Result: Go LUCI Reviewed-by: Meng Zhuo Reviewed-by: Mark Ryan Reviewed-by: Cherry Mui Reviewed-by: Carlos Amedee --- src/math/big/arith_riscv64.s | 81 +++++++++++++++++++++++++++++++++++- 1 file changed, 80 insertions(+), 1 deletion(-) diff --git a/src/math/big/arith_riscv64.s b/src/math/big/arith_riscv64.s index 67812dd646..897d08229e 100644 --- a/src/math/big/arith_riscv64.s +++ b/src/math/big/arith_riscv64.s @@ -92,7 +92,86 @@ done: RET TEXT ·subVV(SB),NOSPLIT,$0 - JMP ·subVV_g(SB) + MOV x+24(FP), X5 + MOV y+48(FP), X6 + MOV z+0(FP), X7 + MOV z_len+8(FP), X30 + + MOV $4, X28 + MOV $0, X29 // b = 0 + + BEQZ X30, done + BLTU X30, X28, loop1 + +loop4: + MOV 0(X5), X8 // x[0] + MOV 0(X6), X9 // y[0] + MOV 8(X5), X11 // x[1] + MOV 8(X6), X12 // y[1] + MOV 16(X5), X14 // x[2] + MOV 16(X6), X15 // y[2] + MOV 24(X5), X17 // x[3] + MOV 24(X6), X18 // y[3] + + SUB X9, X8, X21 // z[0] = x[0] - y[0] + SLTU X21, X8, X22 + SUB X29, X21, X10 // z[0] = x[0] - y[0] - b + SLTU X10, X21, X23 + ADD X22, X23, X29 // next b + + SUB X12, X11, X24 // z[1] = x[1] - y[1] + SLTU X24, X11, X25 + SUB X29, X24, X13 // z[1] = x[1] - y[1] - b + SLTU X13, X24, X26 + ADD X25, X26, X29 // next b + + SUB X15, X14, X21 // z[2] = x[2] - y[2] + SLTU X21, X14, X22 + SUB X29, X21, X16 // z[2] = x[2] - y[2] - b + SLTU X16, X21, X23 + ADD X22, X23, X29 // next b + + SUB X18, X17, X21 // z[3] = x[3] - y[3] + SLTU X21, X17, X22 + SUB X29, X21, X19 // z[3] = x[3] - y[3] - b + SLTU X19, X21, X23 + ADD X22, X23, X29 // next b + + MOV X10, 0(X7) // z[0] + MOV X13, 8(X7) // z[1] + MOV X16, 16(X7) // z[2] + MOV X19, 24(X7) // z[3] + + ADD $32, X5 + ADD $32, X6 + ADD $32, X7 + SUB $4, X30 + + BGEU X30, X28, loop4 + BEQZ X30, done + +loop1: + MOV 0(X5), X10 // x + MOV 0(X6), X11 // y + + SUB X11, X10, X12 // z = x - y + SLTU X12, X10, X14 + SUB X29, X12, X13 // z = x - y - b + SLTU X13, X12, X15 + ADD X14, X15, X29 // next b + + MOV X13, 0(X7) // z + + ADD $8, X5 + ADD $8, X6 + ADD $8, X7 + SUB $1, X30 + + BNEZ X30, loop1 + +done: + MOV X29, c+72(FP) // return b + RET TEXT ·addVW(SB),NOSPLIT,$0 JMP ·addVW_g(SB) -- 2.48.1