projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| d5a80657 KM |
1 | #ifndef lint |
| 2 | .asciz "@(#)udiv.s 5.1 (Berkeley) %G%" | |
| 3 | #endif not lint | |
| 43e1c702 BJ |
4 | |
| 5 | /* | |
| 6 | * udiv - unsigned division for vax-11 | |
| 7 | * | |
| 8 | * arguments: dividend, divisor. | |
| 9 | * result: quotient. | |
| 10 | * uses r0-r2 | |
| 11 | * | |
| 12 | * If 1 < divisor <= 2147483647, zero-extend the dividend | |
| 13 | * to 64 bits and let ediv do the work. If the divisor is 1, | |
| 14 | * ediv will overflow if bit 31 of the dividend is on, so | |
| 15 | * just return the dividend unchanged. If the divisor is 0, | |
| 16 | * do the ediv also, so it will generate the proper exception. | |
| 17 | * All other values of the divisor have bit 31 on: in this case | |
| 18 | * the quotient must be 0 if divisor > dividend, and 1 otherwise, | |
| 19 | * provided that the comparison is made as unsigned. | |
| 20 | */ | |
| 21 | ||
| 22 | #include "DEFS.h" | |
| 23 | ||
| dadab5a2 | 24 | ASENTRY(udiv, 0) |
| 43e1c702 BJ |
25 | movl 4(ap),r0 /* dividend */ |
| 26 | movl 8(ap),r2 /* divisor */ | |
| 27 | jeql 1f /* if divisor=0, force exception */ | |
| 28 | cmpl r2,$1 /* if divisor <= 1 (signed), */ | |
| 29 | jleq 2f /* no division is necessary */ | |
| 30 | 1: | |
| 31 | clrl r1 /* zero-extend the dividend */ | |
| 32 | ediv r2,r0,r0,r2 /* divide. q->r0, r->r2 (discarded) */ | |
| 33 | ret | |
| 34 | 2: | |
| 35 | jeql 1f /* if divisor=1, return dividend */ | |
| 36 | cmpl r0,r2 /* unsigned comparison between */ | |
| 37 | jgequ 2f /* dividend and divisor */ | |
| 38 | clrl r0 /* dividend < divisor, return 0 */ | |
| 39 | ret | |
| 40 | 2: | |
| 41 | movl $1,r0 /* dividend >= divisor, return 1 */ | |
| 42 | 1: | |
| 43 | ret | |
| 294ae850 RC |
44 | |
| 45 | /* | |
| 46 | * audiv - unsigned division for vax-11 | |
| 47 | * | |
| 48 | * arguments: *dividend, divisor. | |
| 49 | * result: quotient in r0 and *dividend. | |
| 50 | * uses r0-r2 | |
| 51 | */ | |
| 52 | ||
| 53 | #include "DEFS.h" | |
| 54 | ||
| 55 | ASENTRY(audiv, 0) | |
| 56 | movl *4(ap),r0 /* dividend */ | |
| 57 | movl 8(ap),r2 /* divisor */ | |
| 58 | jeql 1f /* if divisor=0, force exception */ | |
| 59 | cmpl r2,$1 /* if divisor <= 1 (signed), */ | |
| 60 | jleq 2f /* no division is necessary */ | |
| 61 | 1: | |
| 62 | clrl r1 /* zero-extend the dividend */ | |
| 63 | ediv r2,r0,r0,r2 /* divide. q->r0, r->r2 (discarded) */ | |
| 64 | movl r0,*4(ap) /* save result */ | |
| 65 | ret | |
| 66 | 2: | |
| 67 | jeql 1f /* if divisor=1, return dividend */ | |
| 68 | cmpl r0,r2 /* unsigned comparison between */ | |
| 69 | jgequ 2f /* dividend and divisor */ | |
| 70 | clrl r0 /* dividend < divisor, return 0 */ | |
| 71 | clrl *4(ap) /* save result */ | |
| 72 | ret | |
| 73 | 2: | |
| 74 | movl $1,r0 /* dividend >= divisor, return 1 */ | |
| 75 | 1: | |
| 76 | movl r0,*4(ap) /* save result */ | |
| 77 | ret |