openpcd/firmware/include/asm/div64.h @ master
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#ifndef __ASM_ARM_DIV64
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#define __ASM_ARM_DIV64
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#include <asm/system.h>
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/*
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* The semantics of do_div() are:
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*
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* uint32_t do_div(uint64_t *n, uint32_t base)
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* {
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* uint32_t remainder = *n % base;
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* *n = *n / base;
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* return remainder;
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* }
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*
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* In other words, a 64-bit dividend with a 32-bit divisor producing
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* a 64-bit result and a 32-bit remainder. To accomplish this optimally
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* we call a special __do_div64 helper with completely non standard
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* calling convention for arguments and results (beware).
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*/
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#ifdef __ARMEB__
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#define __xh "r0"
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#define __xl "r1"
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#else
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#define __xl "r0"
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#define __xh "r1"
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#endif
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#define do_div(n,base) \
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({ \
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register unsigned int __base asm("r4") = base; \
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register unsigned long long __n asm("r0") = n; \
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register unsigned long long __res asm("r2"); \
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register unsigned int __rem asm(__xh); \
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asm( __asmeq("%0", __xh) \
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__asmeq("%1", "r2") \
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__asmeq("%2", "r0") \
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__asmeq("%3", "r4") \
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"bl __do_div64" \
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: "=r" (__rem), "=r" (__res) \
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: "r" (__n), "r" (__base) \
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: "ip", "lr", "cc"); \
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n = __res; \
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__rem; \
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})
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#endif
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