// 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(SB),NOSPLIT,$0-56 // R4 = a_base // R5 = a_len // R6 = a_cap (unused) // R7 = b_base (want in R6) // R8 = b_len (want in R7) // R9 = b_cap (unused) MOVV R7, R6 MOVV R8, R7 JMP cmpbody<>(SB) TEXT runtime·cmpstring(SB),NOSPLIT,$0-40 // R4 = a_base // R5 = a_len // R6 = b_base // R7 = b_len JMP cmpbody<>(SB) // On entry: // R5 length of a // R7 length of b // R4 points to the start of a // R6 points to the start of b // R13 points to the return value (-1/0/1) TEXT cmpbody<>(SB),NOSPLIT|NOFRAME,$0 BEQ R4, R6, samebytes // same start of a and b SGTU R5, R7, R9 BNE R0, R9, r2_lt_r1 MOVV R5, R14 JMP entry r2_lt_r1: MOVV R7, R14 // R14 is min(R4, R5) entry: ADDV R4, R14, R12 // R6 start of a, R14 end of a BEQ R4, R12, samebytes // length is 0 SRLV $4, R14 // R14 is number of chunks BEQ R0, R14, byte_loop // make sure both a and b are aligned. OR R4, R6, R15 AND $7, R15 BNE R0, R15, byte_loop PCALIGN $16 chunk16_loop: BEQ R0, R14, byte_loop MOVV (R4), R8 MOVV (R6), R9 BNE R8, R9, byte_loop MOVV 8(R4), R16 MOVV 8(R6), R17 ADDV $16, R4 ADDV $16, R6 SUBVU $1, R14 BEQ R16, R17, chunk16_loop SUBV $8, R4 SUBV $8, R6 byte_loop: BEQ R4, R12, samebytes MOVBU (R4), R8 ADDVU $1, R4 MOVBU (R6), R9 ADDVU $1, R6 BEQ R8, R9, byte_loop byte_cmp: SGTU R8, R9, R4 // R12 = 1 if (R8 > R9) BNE R0, R4, ret MOVV $-1, R4 JMP ret samebytes: SGTU R5, R7, R8 SGTU R7, R5, R9 SUBV R9, R8, R4 ret: RET