projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | #ifndef __ASM_ARM_DIV64 |
| 2 | #define __ASM_ARM_DIV64 | |
| 3 | ||
| 4 | #include <asm/system.h> | |
| 5 | ||
| 6 | /* | |
| 7 | * The semantics of do_div() are: | |
| 8 | * | |
| 9 | * uint32_t do_div(uint64_t *n, uint32_t base) | |
| 10 | * { | |
| 11 | * uint32_t remainder = *n % base; | |
| 12 | * *n = *n / base; | |
| 13 | * return remainder; | |
| 14 | * } | |
| 15 | * | |
| 16 | * In other words, a 64-bit dividend with a 32-bit divisor producing | |
| 17 | * a 64-bit result and a 32-bit remainder. To accomplish this optimally | |
| 18 | * we call a special __do_div64 helper with completely non standard | |
| 19 | * calling convention for arguments and results (beware). | |
| 20 | */ | |
| 21 | ||
| 22 | #ifdef __ARMEB__ | |
| 23 | #define __xh "r0" | |
| 24 | #define __xl "r1" | |
| 25 | #else | |
| 26 | #define __xl "r0" | |
| 27 | #define __xh "r1" | |
| 28 | #endif | |
| 29 | ||
| 30 | #define do_div(n,base) \ | |
| 31 | ({ \ | |
| 32 | register unsigned int __base asm("r4") = base; \ | |
| 33 | register unsigned long long __n asm("r0") = n; \ | |
| 34 | register unsigned long long __res asm("r2"); \ | |
| 35 | register unsigned int __rem asm(__xh); \ | |
| 36 | asm( __asmeq("%0", __xh) \ | |
| 37 | __asmeq("%1", "r2") \ | |
| 38 | __asmeq("%2", "r0") \ | |
| 39 | __asmeq("%3", "r4") \ | |
| 40 | "bl __do_div64" \ | |
| 41 | : "=r" (__rem), "=r" (__res) \ | |
| 42 | : "r" (__n), "r" (__base) \ | |
| 43 | : "ip", "lr", "cc"); \ | |
| 44 | n = __res; \ | |
| 45 | __rem; \ | |
| 46 | }) | |
| 47 | ||
| 48 | #endif |