diff options
Diffstat (limited to 'src/internal/bytealg/compare_riscv64.s')
| -rw-r--r-- | src/internal/bytealg/compare_riscv64.s | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/src/internal/bytealg/compare_riscv64.s b/src/internal/bytealg/compare_riscv64.s new file mode 100644 index 0000000..44a743d --- /dev/null +++ b/src/internal/bytealg/compare_riscv64.s @@ -0,0 +1,187 @@ +// Copyright 2022 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "go_asm.h" +#include "textflag.h" + +TEXT ·Compare<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-56 + // X10 = a_base + // X11 = a_len + // X12 = a_cap (unused) + // X13 = b_base (want in X12) + // X14 = b_len (want in X13) + // X15 = b_cap (unused) + MOV X13, X12 + MOV X14, X13 + JMP compare<>(SB) + +TEXT runtime·cmpstring<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-40 + // X10 = a_base + // X11 = a_len + // X12 = b_base + // X13 = b_len + JMP compare<>(SB) + +// On entry: +// X10 points to start of a +// X11 length of a +// X12 points to start of b +// X13 length of b +// for non-regabi X14 points to the address to store the return value (-1/0/1) +// for regabi the return value in X10 +TEXT compare<>(SB),NOSPLIT|NOFRAME,$0 + BEQ X10, X12, cmp_len + + MOV X11, X5 + BGE X13, X5, use_a_len // X5 = min(len(a), len(b)) + MOV X13, X5 +use_a_len: + BEQZ X5, cmp_len + + MOV $32, X6 + BLT X5, X6, loop4_check + + // Check alignment - if alignment differs we have to do one byte at a time. + AND $7, X10, X7 + AND $7, X12, X8 + BNE X7, X8, loop4_check + BEQZ X7, loop32_check + + // Check one byte at a time until we reach 8 byte alignment. + SUB X7, X5, X5 +align: + ADD $-1, X7 + MOVBU 0(X10), X8 + MOVBU 0(X12), X9 + BNE X8, X9, cmp + ADD $1, X10 + ADD $1, X12 + BNEZ X7, align + +loop32_check: + MOV $32, X7 + BLT X5, X7, loop16_check +loop32: + MOV 0(X10), X15 + MOV 0(X12), X16 + MOV 8(X10), X17 + MOV 8(X12), X18 + BEQ X15, X16, loop32a + JMP cmp8a +loop32a: + BEQ X17, X18, loop32b + JMP cmp8b +loop32b: + MOV 16(X10), X15 + MOV 16(X12), X16 + MOV 24(X10), X17 + MOV 24(X12), X18 + BEQ X15, X16, loop32c + JMP cmp8a +loop32c: + BEQ X17, X18, loop32d + JMP cmp8b +loop32d: + ADD $32, X10 + ADD $32, X12 + ADD $-32, X5 + BGE X5, X7, loop32 + BEQZ X5, cmp_len + +loop16_check: + MOV $16, X6 + BLT X5, X6, loop4_check +loop16: + MOV 0(X10), X15 + MOV 0(X12), X16 + MOV 8(X10), X17 + MOV 8(X12), X18 + BEQ X15, X16, loop16a + JMP cmp8a +loop16a: + BEQ X17, X18, loop16b + JMP cmp8b +loop16b: + ADD $16, X10 + ADD $16, X12 + ADD $-16, X5 + BGE X5, X6, loop16 + BEQZ X5, cmp_len + +loop4_check: + MOV $4, X6 + BLT X5, X6, loop1 +loop4: + MOVBU 0(X10), X8 + MOVBU 0(X12), X9 + MOVBU 1(X10), X15 + MOVBU 1(X12), X16 + BEQ X8, X9, loop4a + SLTU X9, X8, X5 + SLTU X8, X9, X6 + JMP cmp_ret +loop4a: + BEQ X15, X16, loop4b + SLTU X16, X15, X5 + SLTU X15, X16, X6 + JMP cmp_ret +loop4b: + MOVBU 2(X10), X21 + MOVBU 2(X12), X22 + MOVBU 3(X10), X23 + MOVBU 3(X12), X24 + BEQ X21, X22, loop4c + SLTU X22, X21, X5 + SLTU X21, X22, X6 + JMP cmp_ret +loop4c: + BEQ X23, X24, loop4d + SLTU X24, X23, X5 + SLTU X23, X24, X6 + JMP cmp_ret +loop4d: + ADD $4, X10 + ADD $4, X12 + ADD $-4, X5 + BGE X5, X6, loop4 + +loop1: + BEQZ X5, cmp_len + MOVBU 0(X10), X8 + MOVBU 0(X12), X9 + BNE X8, X9, cmp + ADD $1, X10 + ADD $1, X12 + ADD $-1, X5 + JMP loop1 + + // Compare 8 bytes of memory in X15/X16 that are known to differ. +cmp8a: + MOV $0xff, X19 +cmp8a_loop: + AND X15, X19, X8 + AND X16, X19, X9 + BNE X8, X9, cmp + SLLI $8, X19 + JMP cmp8a_loop + + // Compare 8 bytes of memory in X17/X18 that are known to differ. +cmp8b: + MOV $0xff, X19 +cmp8b_loop: + AND X17, X19, X8 + AND X18, X19, X9 + BNE X8, X9, cmp + SLLI $8, X19 + JMP cmp8b_loop + +cmp_len: + MOV X11, X8 + MOV X13, X9 +cmp: + SLTU X9, X8, X5 + SLTU X8, X9, X6 +cmp_ret: + SUB X5, X6, X10 + RET |