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f7ea46e49e
Added a release config, and fixed a few spots where optimizations broke things: - Clang was generating incorrect code for run_ctor_list in libc's init.cpp (it ignored a check for the end of the list) - my rep movsb memcpy implementation used incorrect inline asm constraints, so it was returning a pointer to the end of the copied range instead of the start. Since this function was just inline asm anyway, I rewrote it in asm by hand in a new memutils.s file.
67 lines
1.5 KiB
C++
67 lines
1.5 KiB
C++
#include <stddef.h>
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#include <j6/memutils.h>
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#include <__j6libc/bits.h>
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#include <__j6libc/casts.h>
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#include "copy.h"
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using namespace j6;
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using namespace __j6libc;
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static void memmove_dispatch(char *s1, const char *s2, size_t n) {
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if (s1 == s2) return;
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if (s1 < s2 || s1 > s2 + n)
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memcpy(s1, s2, n);
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else
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do_backward_copy(s1, s2, n);
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}
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void *memmove(void * restrict s1, const void * restrict s2, size_t n) {
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memmove_dispatch(
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reinterpret_cast<char*>(s1),
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reinterpret_cast<const char*>(s1),
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n);
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return s1;
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}
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#if __UINTPTR_WIDTH__ != 64 && __UINTPTR_WIDTH__ != 32
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#error "memset: uintptr_t isn't 4 or 8 bytes"
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#endif
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static inline uintptr_t repval(uint8_t c) {
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uintptr_t r = c;
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r |= r << 8;
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r |= r << 16;
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#if __UINTPTR_WIDTH__ == 64
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r |= r << 32;
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#endif
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return r;
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}
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void *memset(void *s, int c, size_t n) {
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if (!s) return nullptr;
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// First, any unalined initial bytes
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uint8_t *b = cast_to<uint8_t*>(s);
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uint8_t bval = c & 0xff;
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while (n && !is_aligned<uintptr_t>(b)) {
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*b++ = bval;
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--n;
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}
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// As many word-sized writes as possible
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size_t words = n >> word_shift;
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uintptr_t pval = repval(c);
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uintptr_t *p = cast_to<uintptr_t*>(b);
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for (size_t i = 0; i < words; ++i)
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*p++ = pval;
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// Remaining unaligned bytes
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b = reinterpret_cast<uint8_t*>(p);
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size_t remainder = n & word_align_mask;
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for (size_t i = 0; i < remainder; ++i)
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*b++ = bval;
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return s;
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} |