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Annotation of researchv10no/libc/gen/memcpy.s, revision 1.1.1.1

1.1       root        1:        .file   "memcpy.s"
                      2: #      @(#)memcpy.s    1.5
                      3: # Fast assembler language version of the following C-program
                      4: #                      memcpy
                      5: # which represents the `standard' for the C-library.
                      6: 
                      7: # Copy s2 to s1, always copy n bytes.
                      8: # Return s1
                      9: 
                     10: #      char *
                     11: #      memcpy(s1, s2, n)
                     12: #      register char *s1, *s2;
                     13: #      register int n;
                     14: #      {
                     15: #              register char *os1 = s1;
                     16: #      
                     17: #              while (--n >= 0)
                     18: #                      *s1++ = *s2++;
                     19: #              return (os1);
                     20: #      }
                     21:        .globl  _memcpy
                     22:        .text
                     23:        .align  2
                     24: _memcpy:
                     25:        .word   0x0040          # uses regs. 0,1,2,3,4,5,6
                     26:        movl    12(ap),r6       # length (arg `n')
                     27:        bleq    L2              # n <= 0, so return now!
                     28:        movq    4(ap),r3        # dest ptr s1
                     29:        movl    r4,r1           # src ptr s2
                     30: L0:
                     31:        cmpl    $65535,r6       # is len VERY large?
                     32:        bgeq    L1              # hop if not
                     33:        movc3   $65535,(r1),(r3)        # Move n bytes
                     34:        subl2   $65535,r6
                     35:        jbr     L0              # go move some more string
                     36: L1:
                     37:        movc3   r6,(r1),(r3)    # Move n bytes
                     38: L2:
                     39:        movl    4(ap),r0        # we're done - return s1
                     40:        ret

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