1 // Copyright 2013 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 #include "textflag.h" 6 7 // func xorKeyStream(dst, src *byte, n int, state *[256]byte, i, j *uint8) 8 TEXT xorKeyStream(SB),NOSPLIT,$0 9 MOVL dst+0(FP), DI 10 MOVL src+4(FP), SI 11 MOVL state+12(FP), BP 12 13 MOVL i+16(FP), AX 14 MOVBLZX (AX), AX 15 MOVL j+20(FP), BX 16 MOVBLZX (BX), BX 17 CMPL n+8(FP), $0 18 JEQ done 19 20 loop: 21 // i += 1 22 INCB AX 23 24 // j += c.s[i] 25 MOVBLZX (BP)(AX*4), DX 26 ADDB DX, BX 27 MOVBLZX BX, BX 28 29 // c.s[i], c.s[j] = c.s[j], c.s[i] 30 MOVBLZX (BP)(BX*4), CX 31 MOVB CX, (BP)(AX*4) 32 MOVB DX, (BP)(BX*4) 33 34 // *dst = *src ^ c.s[c.s[i]+c.s[j]] 35 ADDB DX, CX 36 MOVBLZX CX, CX 37 MOVB (BP)(CX*4), CX 38 XORB (SI), CX 39 MOVBLZX CX, CX 40 MOVB CX, (DI) 41 42 INCL SI 43 INCL DI 44 DECL n+8(FP) 45 JNE loop 46 47 done: 48 MOVL i+16(FP), CX 49 MOVB AX, (CX) 50 MOVL j+20(FP), CX 51 MOVB BX, (CX) 52 53 RET 54
