1 #ifndef __ASM_ARM_DIV64 2 #define __ASM_ARM_DIV64 3 4 #include <linux/types.h> 5 #include <asm/compiler.h> 6 7 /* 8 * The semantics of __div64_32() are: 9 * 10 * uint32_t __div64_32(uint64_t *n, uint32_t base) 11 * { 12 * uint32_t remainder = *n % base; 13 * *n = *n / base; 14 * return remainder; 15 * } 16 * 17 * In other words, a 64-bit dividend with a 32-bit divisor producing 18 * a 64-bit result and a 32-bit remainder. To accomplish this optimally 19 * we override the generic version in lib/div64.c to call our __do_div64 20 * assembly implementation with completely non standard calling convention 21 * for arguments and results (beware). 22 */ 23 24 #ifdef __ARMEB__ 25 #define __xh "r0" 26 #define __xl "r1" 27 #else 28 #define __xl "r0" 29 #define __xh "r1" 30 #endif 31 32 static inline uint32_t __div64_32(uint64_t *n, uint32_t base) 33 { 34 register unsigned int __base asm("r4") = base; 35 register unsigned long long __n asm("r0") = *n; 36 register unsigned long long __res asm("r2"); 37 register unsigned int __rem asm(__xh); 38 asm( __asmeq("%0", __xh) 39 __asmeq("%1", "r2") 40 __asmeq("%2", "r0") 41 __asmeq("%3", "r4") 42 "bl __do_div64" 43 : "=r" (__rem), "=r" (__res) 44 : "r" (__n), "r" (__base) 45 : "ip", "lr", "cc"); 46 *n = __res; 47 return __rem; 48 } 49 #define __div64_32 __div64_32 50 51 #if !defined(CONFIG_AEABI) 52 53 /* 54 * In OABI configurations, some uses of the do_div function 55 * cause gcc to run out of registers. To work around that, 56 * we can force the use of the out-of-line version for 57 * configurations that build a OABI kernel. 58 */ 59 #define do_div(n, base) __div64_32(&(n), base) 60 61 #else 62 63 /* 64 * gcc versions earlier than 4.0 are simply too problematic for the 65 * __div64_const32() code in asm-generic/div64.h. First there is 66 * gcc PR 15089 that tend to trig on more complex constructs, spurious 67 * .global __udivsi3 are inserted even if none of those symbols are 68 * referenced in the generated code, and those gcc versions are not able 69 * to do constant propagation on long long values anyway. 70 */ 71 72 #define __div64_const32_is_OK (__GNUC__ >= 4) 73 74 static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias) 75 { 76 unsigned long long res; 77 unsigned int tmp = 0; 78 79 if (!bias) { 80 asm ( "umull %Q0, %R0, %Q1, %Q2\n\t" 81 "mov %Q0, #0" 82 : "=&r" (res) 83 : "r" (m), "r" (n) 84 : "cc"); 85 } else if (!(m & ((1ULL << 63) | (1ULL << 31)))) { 86 res = m; 87 asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t" 88 "mov %Q0, #0" 89 : "+&r" (res) 90 : "r" (m), "r" (n) 91 : "cc"); 92 } else { 93 asm ( "umull %Q0, %R0, %Q1, %Q2\n\t" 94 "cmn %Q0, %Q1\n\t" 95 "adcs %R0, %R0, %R1\n\t" 96 "adc %Q0, %3, #0" 97 : "=&r" (res) 98 : "r" (m), "r" (n), "r" (tmp) 99 : "cc"); 100 } 101 102 if (!(m & ((1ULL << 63) | (1ULL << 31)))) { 103 asm ( "umlal %R0, %Q0, %R1, %Q2\n\t" 104 "umlal %R0, %Q0, %Q1, %R2\n\t" 105 "mov %R0, #0\n\t" 106 "umlal %Q0, %R0, %R1, %R2" 107 : "+&r" (res) 108 : "r" (m), "r" (n) 109 : "cc"); 110 } else { 111 asm ( "umlal %R0, %Q0, %R2, %Q3\n\t" 112 "umlal %R0, %1, %Q2, %R3\n\t" 113 "mov %R0, #0\n\t" 114 "adds %Q0, %1, %Q0\n\t" 115 "adc %R0, %R0, #0\n\t" 116 "umlal %Q0, %R0, %R2, %R3" 117 : "+&r" (res), "+&r" (tmp) 118 : "r" (m), "r" (n) 119 : "cc"); 120 } 121 122 return res; 123 } 124 #define __arch_xprod_64 __arch_xprod_64 125 126 #include <asm-generic/div64.h> 127 128 #endif 129 130 #endif 131