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 49
