Annotation of researchv10no/libc/gen/strcpy.s, revision 1.1

1.1     ! root        1:        .file   "strcpy.s"
        !             2: #      @(#)strcpy.s    1.5
        !             3: # Fast assembler language version of the following C-program
        !             4: #                      strcpy
        !             5: # which represents the `standard' for the C-library.
        !             6: 
        !             7: # Copy string s2 to s1.  s1 must be large enough. Return s1.
        !             8: 
        !             9: #      char *
        !            10: #      strcpy(s1, s2)
        !            11: #      register char *s1, *s2;
        !            12: #      {
        !            13: #              register char *os1;
        !            14: #      
        !            15: #              os1 = s1;
        !            16: #              while (*s1++ = *s2++)
        !            17: #                      ;
        !            18: #              return(os1);
        !            19: #      }
        !            20:        .globl  _strcpy
        !            21:        .text
        !            22:        .align  2
        !            23: _strcpy:
        !            24:        .word   0x00c0                  # use regs. 0,1,2,3,4,5,6,7
        !            25:        movq    4(ap),r6                # dest. in r6, src. in r7
        !            26:        movl    r6,r3                   # working copy of dest. in r3
        !            27: L0:
        !            28:        locc    $0,$65535,(r7)          # try to find null in src.
        !            29:        bneq    L1                      # skip if null found -
        !            30:        movc3   $65535,(r7),(r3)        # else move BLOCK of chars
        !            31:        movl    r1,r7                   #   and adjust pointers to
        !            32:        jmp     L0                      #   go back and try again
        !            33: L1:
        !            34:        subl2   r7,r1                   # length (but 1) of src.
        !            35:        incl    r1                      # adjust length to cover null
        !            36:        movc3   r1,(r7),(r3)            # move string including null
        !            37:        movl    r6,r0                   # return dest.
        !            38:        ret

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