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Diffstat (limited to 'src/internal/bytealg/equal_ppc64x.s')
| -rw-r--r-- | src/internal/bytealg/equal_ppc64x.s | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/src/internal/bytealg/equal_ppc64x.s b/src/internal/bytealg/equal_ppc64x.s new file mode 100644 index 0000000..f2c7cc1 --- /dev/null +++ b/src/internal/bytealg/equal_ppc64x.s @@ -0,0 +1,205 @@ +// Copyright 2018 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. + +//go:build ppc64 || ppc64le + +#include "go_asm.h" +#include "textflag.h" + +// 4K (smallest case) page size offset mask for PPC64. +#define PAGE_OFFSET 4095 + +// TODO: At writing, ISEL and BC do not support CR bit type arguments, +// define them here for readability. +#define CR0LT 4*0+0 +#define CR0EQ 4*0+2 +#define CR1LT 4*1+0 +#define CR6LT 4*6+0 + +// Likewise, the BC opcode is hard to read, and no extended +// mnemonics are offered for these forms. +#define BGELR_CR6 BC 4, CR6LT, (LR) +#define BEQLR BC 12, CR0EQ, (LR) + +// memequal(a, b unsafe.Pointer, size uintptr) bool +TEXT runtime·memequal<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-25 + // R3 = a + // R4 = b + // R5 = size + BR memeqbody<>(SB) + +// memequal_varlen(a, b unsafe.Pointer) bool +TEXT runtime·memequal_varlen<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-17 + // R3 = a + // R4 = b + CMP R3, R4 + BEQ eq + MOVD 8(R11), R5 // compiler stores size at offset 8 in the closure + BR memeqbody<>(SB) +eq: + MOVD $1, R3 + RET + +// Do an efficient memequal for ppc64 +// R3 = s1 +// R4 = s2 +// R5 = len +// On exit: +// R3 = return value +TEXT memeqbody<>(SB),NOSPLIT|NOFRAME,$0-0 + MOVD R3, R8 // Move s1 into R8 + ADD R5, R3, R9 // &s1[len(s1)] + ADD R5, R4, R10 // &s2[len(s2)] + MOVD $1, R11 + CMP R5, $16 // Use GPR checks for check for len <= 16 + BLE check0_16 + MOVD $0, R3 // Assume no-match in case BGELR CR6 returns + CMP R5, $32 // Use overlapping VSX loads for len <= 32 + BLE check17_32 // Do a pair of overlapping VSR compares + CMP R5, $64 + BLE check33_64 // Hybrid check + overlap compare. + +setup64: + SRD $6, R5, R6 // number of 64 byte chunks to compare + MOVD R6, CTR + MOVD $16, R14 // index for VSX loads and stores + MOVD $32, R15 + MOVD $48, R16 + ANDCC $0x3F, R5, R5 // len%64==0? + + PCALIGN $32 +loop64: + LXVD2X (R8+R0), V0 + LXVD2X (R4+R0), V1 + VCMPEQUBCC V0, V1, V2 // compare, setting CR6 + BGELR_CR6 + LXVD2X (R8+R14), V0 + LXVD2X (R4+R14), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + LXVD2X (R8+R15), V0 + LXVD2X (R4+R15), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + LXVD2X (R8+R16), V0 + LXVD2X (R4+R16), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + ADD $64,R8 // bump up to next 64 + ADD $64,R4 + BDNZ loop64 + + ISEL $CR0EQ, R11, R3, R3 // If no tail, return 1, otherwise R3 remains 0. + BEQLR // return if no tail. + + ADD $-64, R9, R8 + ADD $-64, R10, R4 + LXVD2X (R8+R0), V0 + LXVD2X (R4+R0), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + LXVD2X (R8+R14), V0 + LXVD2X (R4+R14), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + LXVD2X (R8+R15), V0 + LXVD2X (R4+R15), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + LXVD2X (R8+R16), V0 + LXVD2X (R4+R16), V1 + VCMPEQUBCC V0, V1, V2 + ISEL $CR6LT, R11, R0, R3 + RET + +check33_64: + // Bytes 0-15 + LXVD2X (R8+R0), V0 + LXVD2X (R4+R0), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + ADD $16, R8 + ADD $16, R4 + + // Bytes 16-31 + LXVD2X (R8+R0), V0 + LXVD2X (R4+R0), V1 + VCMPEQUBCC V0, V1, V2 + BGELR_CR6 + + // A little tricky, but point R4,R8 to &sx[len-32], + // and reuse check17_32 to check the next 1-31 bytes (with some overlap) + ADD $-32, R9, R8 + ADD $-32, R10, R4 + // Fallthrough + +check17_32: + LXVD2X (R8+R0), V0 + LXVD2X (R4+R0), V1 + VCMPEQUBCC V0, V1, V2 + ISEL $CR6LT, R11, R0, R5 + + // Load sX[len(sX)-16:len(sX)] and compare. + ADD $-16, R9 + ADD $-16, R10 + LXVD2X (R9+R0), V0 + LXVD2X (R10+R0), V1 + VCMPEQUBCC V0, V1, V2 + ISEL $CR6LT, R5, R0, R3 + RET + +check0_16: + CMP R5, $8 + BLT check0_7 + // Load sX[0:7] and compare. + MOVD (R8), R6 + MOVD (R4), R7 + CMP R6, R7 + ISEL $CR0EQ, R11, R0, R5 + // Load sX[len(sX)-8:len(sX)] and compare. + MOVD -8(R9), R6 + MOVD -8(R10), R7 + CMP R6, R7 + ISEL $CR0EQ, R5, R0, R3 + RET + +check0_7: + CMP R5,$0 + MOVD $1, R3 + BEQLR // return if len == 0 + + // Check < 8B loads with a single compare, but select the load address + // such that it cannot cross a page boundary. Load a few bytes from the + // lower address if that does not cross the lower page. Or, load a few + // extra bytes from the higher addresses. And align those values + // consistently in register as either address may have differing + // alignment requirements. + ANDCC $PAGE_OFFSET, R8, R6 // &sX & PAGE_OFFSET + ANDCC $PAGE_OFFSET, R4, R9 + SUBC R5, $8, R12 // 8-len + SLD $3, R12, R14 // (8-len)*8 + CMPU R6, R12, CR1 // Enough bytes lower in the page to load lower? + CMPU R9, R12, CR0 + SUB R12, R8, R6 // compute lower load address + SUB R12, R4, R9 + ISEL $CR1LT, R8, R6, R8 // R8 = R6 < 0 ? R8 (&s1) : R6 (&s1 - (8-len)) + ISEL $CR0LT, R4, R9, R4 // Similar for s2 + MOVD (R8), R15 + MOVD (R4), R16 + SLD R14, R15, R7 + SLD R14, R16, R17 + SRD R14, R7, R7 // Clear the upper (8-len) bytes (with 2 shifts) + SRD R14, R17, R17 + SRD R14, R15, R6 // Clear the lower (8-len) bytes + SRD R14, R16, R9 +#ifdef GOARCH_ppc64le + ISEL $CR1LT, R7, R6, R8 // Choose the correct len bytes to compare based on alignment + ISEL $CR0LT, R17, R9, R4 +#else + ISEL $CR1LT, R6, R7, R8 + ISEL $CR0LT, R9, R17, R4 +#endif + CMP R4, R8 + ISEL $CR0EQ, R11, R0, R3 + RET |