.file "strcat.S" .section .text .global _strcat .type _strcat,@function _strcat: ;; On entry: r1 => Destination ;; r2 => Source #ifdef __RX_DISALLOW_STRING_INSNS__ mov r1, r4 ; Save a copy of the dest pointer. 1: mov.b [r4+], r5 ; Find the NUL byte at the end of R4. cmp #0, r5 bne 1b sub #1, r4 ; Move R4 back to point at the NUL byte. 2: mov.b [r2+], r5 ; Copy bytes from R2 to R4 until we reach a NUL byte. mov.b r5, [r4+] cmp #0, r5 bne 2b rts #else mov r1, r4 ; Save a copy of the dest pointer. mov r2, r5 ; Save a copy of the source pointer. mov #0, r2 ; Search for the NUL byte. mov #-1, r3 ; Limit on the number of bytes examined. suntil.b ; Find the end of the destination string. sub #1, r1 ; suntil.b leaves r1 pointing to the byte beyond the match. mov #-1, r3 ; Set a limit on the number of bytes copied. mov r5, r2 ; Restore the source pointer. smovu ; Copy source to destination mov r4, r1 ; Return the original dest pointer. rts #endif .size _strcat, . - _strcat