ref: 25139465363b2230b69789013e3e0b5f82d76564
dir: /sys/src/libc/mips/strcpy.s/
TEXT strcpy(SB), $0 MOVW s2+4(FP),R2 /* R2 is from pointer */ MOVW R1, R3 /* R3 is to pointer */ /* * align 'from' pointer */ l1: AND $3, R2, R5 ADDU $1, R2 BEQ R5, l2 MOVB -1(R2), R5 ADDU $1, R3 MOVB R5, -1(R3) BNE R5, l1 RET /* * test if 'to' is also alligned */ l2: AND $3,R3, R5 BEQ R5, l4 /* * copy 4 at a time, 'to' not aligned */ l3: MOVW -1(R2), R4 ADD $4, R2 ADD $4, R3 SRL $24,R4, R5 MOVB R5, -4(R3) BEQ R5, out SRL $16,R4, R5 AND $0xff, R5 MOVB R5, -3(R3) BEQ R5, out SRL $8,R4, R5 AND $0xff, R5 MOVB R5, -2(R3) BEQ R5, out AND $0xff,R4, R5 MOVB R5, -1(R3) BNE R5, l3 out: RET /* * word at a time both aligned */ l4: MOVW $0xff000000, R7 MOVW $0x00ff0000, R8 l5: ADDU $4, R3 MOVW -1(R2), R4 /* fetch */ ADDU $4, R2 AND R7,R4, R5 /* is it byte 0 */ AND R8,R4, R6 /* is it byte 1 */ BEQ R5, b0 AND $0xff00,R4, R5 /* is it byte 2 */ BEQ R6, b1 AND $0xff,R4, R6 /* is it byte 3 */ BEQ R5, b2 MOVW R4, -4(R3) /* store */ BNE R6, l5 JMP out b0: MOVB $0, -4(R3) JMP out b1: SRL $24, R4 MOVB R4, -4(R3) MOVB $0, -3(R3) JMP out b2: SRL $24,R4, R5 MOVB R5, -4(R3) SRL $16, R4 MOVB R4, -3(R3) MOVB $0, -2(R3) JMP out