diff options
Diffstat (limited to 'src/internal/bytealg/count_ppc64x.s')
| -rw-r--r-- | src/internal/bytealg/count_ppc64x.s | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/src/internal/bytealg/count_ppc64x.s b/src/internal/bytealg/count_ppc64x.s new file mode 100644 index 0000000..a64d7d7 --- /dev/null +++ b/src/internal/bytealg/count_ppc64x.s @@ -0,0 +1,97 @@ +// 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. + +// +build ppc64le ppc64 + +#include "go_asm.h" +#include "textflag.h" + +TEXT ·Count(SB), NOSPLIT|NOFRAME, $0-40 + MOVD b_base+0(FP), R3 // R3 = byte array pointer + MOVD b_len+8(FP), R4 // R4 = length + MOVBZ c+24(FP), R5 // R5 = byte + MOVD $ret+32(FP), R14 // R14 = &ret + BR countbytebody<>(SB) + +TEXT ·CountString(SB), NOSPLIT|NOFRAME, $0-32 + MOVD s_base+0(FP), R3 // R3 = string + MOVD s_len+8(FP), R4 // R4 = length + MOVBZ c+16(FP), R5 // R5 = byte + MOVD $ret+24(FP), R14 // R14 = &ret + BR countbytebody<>(SB) + +// R3: addr of string +// R4: len of string +// R5: byte to count +// R14: addr for return value +// endianness shouldn't matter since we are just counting and order +// is irrelevant +TEXT countbytebody<>(SB), NOSPLIT|NOFRAME, $0-0 + DCBT (R3) // Prepare cache line. + MOVD R0, R18 // byte count + MOVD R3, R19 // Save base address for calculating the index later. + MOVD R4, R16 + + MOVD R5, R6 + RLDIMI $8, R6, $48, R6 + RLDIMI $16, R6, $32, R6 + RLDIMI $32, R6, $0, R6 // fill reg with the byte to count + + VSPLTISW $3, V4 // used for shift + MTVRD R6, V1 // move compare byte + VSPLTB $7, V1, V1 // replicate byte across V1 + + CMPU R4, $32 // Check if it's a small string (<32 bytes) + BLT tail // Jump to the small string case + XXLXOR VS37, VS37, VS37 // clear V5 (aka VS37) to use as accumulator + +cmploop: + LXVW4X (R3), VS32 // load bytes from string + + // when the bytes match, the corresponding byte contains all 1s + VCMPEQUB V1, V0, V2 // compare bytes + VPOPCNTD V2, V3 // each double word contains its count + VADDUDM V3, V5, V5 // accumulate bit count in each double word + ADD $16, R3, R3 // increment pointer + SUB $16, R16, R16 // remaining bytes + CMP R16, $16 // at least 16 remaining? + BGE cmploop + VSRD V5, V4, V5 // shift by 3 to convert bits to bytes + VSLDOI $8, V5, V5, V6 // get the double word values from vector + MFVSRD V5, R9 + MFVSRD V6, R10 + ADD R9, R10, R9 + ADD R9, R18, R18 + +tail: + CMP R16, $8 // 8 bytes left? + BLT small + + MOVD (R3), R12 // load 8 bytes + CMPB R12, R6, R17 // compare bytes + POPCNTD R17, R15 // bit count + SRD $3, R15, R15 // byte count + ADD R15, R18, R18 // add to byte count + +next1: + ADD $8, R3, R3 + SUB $8, R16, R16 // remaining bytes + BR tail + +small: + CMP $0, R16 // any remaining + BEQ done + MOVBZ (R3), R12 // check each remaining byte + CMP R12, R5 + BNE next2 + ADD $1, R18 + +next2: + SUB $1, R16 + ADD $1, R3 // inc address + BR small + +done: + MOVD R18, (R14) // return count + RET |