TTL 'itoa' OPT D *============================================================================== * * i t o a , l t o a * *============================================================================== * int itoa (N, Str) int N; char *Str; * int ltoa (N, Str) long N; char *Str; * * Convert the (signed) integer N to a null-terminated ASCII string * of decimal digits and place in the area pointed to by Str. If N is * negative, the output string begins with a '-'. No leading blanks or * zeros are produced. The function returns the number of characters * placed in the output string, excluding the null terminator. * itoa IDNT SECTION 9 XDEF .itoa XDEF .ltoa * .itoa: .ltoa: link a6,#0 ; create stack frame for saving A6 movem.l d2,-(a7) ; save D2 ; stack now looks like: ; STR ; A6+12 A7+16 ; N ; A6+8 A7+12 ; Return address ; A6+4 A7+8 ; A6 -> A6 ; A6+0 A7+4 ; A7 -> D2 ; A6-4 A7+0 ; move.l 16(a7),a0 ; A0 -> Str move.l 12(a7),d0 ; N bpl.s plus ; OK if N is positive ; neg.l d0 ; N is negative: make it positive move.b #'-',(a0)+ ; Output a '-' sign plus: ; copy number onto stack (backwards), to later copy to str ; move.b #0,-(a7) ; Null-terminator for output string mainlp: ; The main loop cmpi.l #65535,d0 ; Is hi word of number equal 0 ? bhi.s not0 ; long value to convert ; moveq #10,d1 ; amount to divide by div16: ; do 16-bit div cmp.l d1,d0 ; Is number < 10 ? bcs.s done ; yes, we're done ; divu d1,d0 ; no, Divide number by 10 swap d0 ; Quotient in hi, remainder in lo addi.b #'0',d0 ; Convert from binary to ASCII move.b d0,-(a7) ; Save the remainder on stack andi.b #0,d0 ; Clear low order byte swap d0 ; Quotient back to low order word bra div16 ; keep processing until 0 ;; not0: ; Hi word != 0, prepare 32-bit div moveq #0,d1 ; Initialize remainder to 0 moveq #31,d2 ; divide by successive subtractions? div32: ; 32/16-bit division lsl.l #1,d0 roxl.l #1,d1 ; 64-bit left shift cmpi.b #10,d1 ; Remainder > divisor ? bcs.s continue ; subi.b #10,d1 ; if so, subtract it addq.b #1,d0 ; add 1 to quotient continue: dbf d2,div32 ; addi.b #'0',d1 ; Convert from binary to ASCII move.b d1,-(a7) ; Save the remainder on stack bra mainlp ; drop to 16 bit divide when number ; small enough ;; done: ; Last digit not pushed on stack addi.b #'0',d0 ; Convert from binary to ASCII move.b d0,(a0)+ rev: ; Loop for reversing the digits move.b (a7)+,(a0)+ ; Copy output from stack to Str bne rev ; copy up to null at end ; ; stack restored move.l a0,d0 ; Ptr to Str after the null char subq.l #1,d0 sub.l 12(a6),d0 ; end-start = number of chars in string ; including 0 at end of string. ; movem.l -4(a6),d2 ; restore d2 unlk a6 ; reset stack frame to callers rts ; return to caller ;; * END