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Annotation of coherent/b/lib/libc/string/i8086/strrchr.m, revision 1.1.1.1

1.1       root        1: //////////
                      2: / i8086 C string library.
                      3: / strrchr()
                      4: / ANSI 4.11.5.5.
                      5: / Previously known as rindex().
                      6: / Entry point for rindex() retained for backward compatability.
                      7: //////////
                      8: 
                      9: //////////
                     10: / char *
                     11: / strrchr(String, Char)
                     12: / char *String;
                     13: / int Char;
                     14: /
                     15: / Find rightmost occurence of Char in String,
                     16: / return pointer or NULL.
                     17: //////////
                     18: 
                     19: #include <larges.h>
                     20: 
                     21: String =       LEFTARG
                     22: Char   =       String+DPL
                     23: 
                     24:        .globl  strrchr_
                     25: strrchr_:
                     26: 
                     27:        Enter(rindex_)
                     28:        Lds     si, String(bp)  / String address to DS:SI
                     29:        movb    ah, Char(bp)    / Char to AH
                     30:        sub     bx, bx          / Address of last match to BX
                     31:        cld
                     32: 
                     33: 1:     lodsb                   / Fetch String char to AL
                     34:        cmpb    al, ah          / and compare to Char
                     35:        jne     2f              / Mismatch
                     36:        mov     bx, si          / Match, save address
                     37: 
                     38: 2:     orb     al, al          / Test for NUL
                     39:        jne     1b              / Not done
                     40:        or      bx, bx          / End of string, test if match found
                     41:        jne     3f              / Match found
                     42:        mov     ax, bx          / No match, return NULL
                     43: #if    LARGEDATA
                     44:        mov     dx, ax
                     45: #endif
                     46:        jmp     4f              / Go home
                     47: 
                     48: 3:     dec     bx              / Back up to match
                     49:        mov     ax, bx          / AX = offset
                     50: #if    LARGEDATA
                     51:        mov     dx, ds          / DX = segment
                     52: #endif
                     53: 
                     54: 4:     Leave

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