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

1.1       root        1:        .file   "strcpn.s"
                      2: #      @(#)strspn.s    1.6
                      3: # Fast assembler language version of the following C-program
                      4: #                      strspn
                      5: # which represents the `standard' for the C-library.
                      6: 
                      7: #      Return the number of characters in the maximum leading segment
                      8: #      of string which consists solely of characters from charset.
                      9: 
                     10: #      int
                     11: #      strspn(string, charset)
                     12: #      char    *string;
                     13: #      register char   *charset;
                     14: #      {
                     15: #              register char *p, *q;
                     16: #      
                     17: #              for(q=string; *q != '\0'; ++q) {
                     18: #                      for(p=charset; *p != '\0' && *p != *q; ++p)
                     19: #                              ;
                     20: #                      if(*p == '\0')
                     21: #                              break;
                     22: #              }
                     23: #              return(q-string);
                     24: #      }
                     25:        .globl  _strspn
                     26:        .text
                     27:        .align  2
                     28: _strspn:
                     29:        .word   0x0000                  # pgm uses regs 0,1,2,3,4
                     30:        movab   -256(sp),sp             # get table space
                     31:        movc5   $0,(ap),$0,$256,(sp)    # and zero it out
                     32:        movl    8(ap),r0                # charset ptr in r0
                     33:        beql    L5                      # return 0 if arg was NULL
                     34: L0:
                     35:        movzbl  (r0)+,r3                # byte from charset for index
                     36:        beql    L1                      # hop if found ending NULL
                     37:        movb    $255,(sp)[r3]           # make entry in spanc table
                     38:        jmp     L0                      # get next byte from charset
                     39: L1:
                     40:        movl    4(ap),r1                # string ptr in r1
                     41:        beql    L4                      # if it's NULL, return 0
                     42: L2:
                     43:        movl    r1,r4                   # preserve a copy of this ptr
                     44:        locc    $0,$65535,(r1)          # get length of string
                     45:        bneq    L3                      # skip if string not > 65535
                     46:        spanc   $65535,(r4),(sp),$255   # else spanc the first 65535
                     47:        bneq    L4                      # hop ahead if we ended the span
                     48:        jmp     L2                      # else go back and do next 65535
                     49: L3:
                     50:        subl3   r4,r1,r0                # length to end of string in r0
                     51:        spanc   r0,(r4),(sp),$255       # this is the main function
                     52: L4:
                     53:        subl3   4(ap),r1,r0             # length of the span
                     54: L5:
                     55:        movab   256(sp),sp              # restore the stack pointer
                     56:        ret

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