| 329,7 → 329,9 |
|---|
| } |
| |
| |
| /* converts an ASCIIZ string into an unsigned short. returns 0 on success. */ |
| /* converts an ASCIIZ string into an unsigned short. returns 0 on success. |
| * on error, result will contain all valid digits that were read until |
| * error occurred (0 on overflow or if parsing failed immediately) */ |
| int atous(unsigned short *r, const char *s) { |
| int err = 0; |
| |
| 347,18 → 349,21 |
|---|
| jz DONE |
| /* validate that AL is in range '0'-'9' */ |
| sub al, '0' |
| jc FAIL /* neg result */ |
| jc FAIL /* invalid character detected */ |
| cmp al, 9 |
| jg FAIL |
| jg FAIL /* invalid character detected */ |
| /* restore result into AX (CX contains the new digit) */ |
| xchg cx, ax |
| /* multiply result by 10 and add cl */ |
| mul bx /* DX AX = AX * BX(10) */ |
| jc FAIL /* overflow */ |
| jc OVERFLOW /* overflow */ |
| add ax, cx |
| /* if CF then overflow occured (overflow part lands in DX) */ |
| /* if CF is set then overflow occurred (overflow part lands in DX) */ |
| jnc NEXTBYTE |
| |
| OVERFLOW: |
| xor cx, cx /* make sure result is zeroed in case overflow occured */ |
| |
| FAIL: |
| inc [err] |
| |