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-rw-r--r--libc/string/i386/string.h316
1 files changed, 316 insertions, 0 deletions
diff --git a/libc/string/i386/string.h b/libc/string/i386/string.h
new file mode 100644
index 000000000..3eefdeb76
--- /dev/null
+++ b/libc/string/i386/string.h
@@ -0,0 +1,316 @@
+/*
+ * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball
+ */
+
+#if !defined _STRING_H
+#error "Never use <libc-string_i386.h> directly; include <string.h> instead"
+#endif
+
+#ifndef _LIBC_STRING_i386_H
+#define _LIBC_STRING_i386_H 1
+
+static __always_inline
+void *inlined_memset_const_c_count4(void *s, unsigned eax, unsigned count)
+{
+ int ecx, edi;
+
+ if (count == 0)
+ return s;
+
+ /* Very small (2 stores or less) are best done with direct
+ * mov <const>,<mem> instructions (they do not clobber registers) */
+ if (count == 1) {
+ *(char *)(s + 0) = eax;
+ return s;
+ }
+
+ /* You wonder why & 0xff is needed? Try memset(p, '\xff', size).
+ * If char is signed, '\xff' == -1! */
+ eax = (eax & 0xff) * 0x01010101; /* done at compile time */
+
+ if (count == 2) {
+ *(short *)(s + 0) = eax;
+ return s;
+ }
+ if (count == 3) {
+ *(short *)(s + 0) = eax;
+ *(char *) (s + 2) = eax;
+ return s;
+ }
+ if (count == 1*4 + 0) {
+ *(int *)(s + 0) = eax;
+ return s;
+ }
+ if (count == 1*4 + 1) {
+ *(int *) (s + 0) = eax;
+ *(char *)(s + 4) = eax;
+ return s;
+ }
+ if (count == 1*4 + 2) {
+ *(int *) (s + 0) = eax;
+ *(short *)(s + 4) = eax;
+ return s;
+ }
+
+ /* Small string stores: don't clobber ecx
+ * (clobbers only eax and edi) */
+#define small_store(arg) { \
+ __asm__ __volatile__( \
+ arg \
+ : "=&D" (edi) \
+ : "a" (eax), "0" (s) \
+ : "memory" \
+ ); \
+ return s; \
+}
+ if (count == 1*4 + 3) small_store("stosl; stosw; stosb");
+ if (count == 2*4 + 0) {
+ ((int *)s)[0] = eax;
+ ((int *)s)[1] = eax;
+ return s;
+ }
+ if (count == 2*4 + 1) small_store("stosl; stosl; stosb");
+ if (count == 2*4 + 2) small_store("stosl; stosl; stosw");
+ if (count == 2*4 + 3) small_store("stosl; stosl; stosw; stosb");
+ if (count == 3*4 + 0) small_store("stosl; stosl; stosl");
+ if (count == 3*4 + 1) small_store("stosl; stosl; stosl; stosb");
+ if (count == 3*4 + 2) small_store("stosl; stosl; stosl; stosw");
+ if (count == 3*4 + 3) small_store("stosl; stosl; stosl; stosw; stosb");
+ if (count == 4*4 + 0) small_store("stosl; stosl; stosl; stosl");
+ if (count == 4*4 + 1) small_store("stosl; stosl; stosl; stosl; stosb");
+ /* going over 7 bytes is suboptimal */
+ /* stosw is 2-byte insn, so this one takes 6 bytes: */
+ if (count == 4*4 + 2) small_store("stosl; stosl; stosl; stosl; stosw");
+ /* 7 bytes */
+ if (count == 4*4 + 3) small_store("stosl; stosl; stosl; stosl; stosw; stosb");
+ /* 5 bytes */
+ if (count == 5*4 + 0) small_store("stosl; stosl; stosl; stosl; stosl");
+ /* 6 bytes */
+ if (count == 5*4 + 1) small_store("stosl; stosl; stosl; stosl; stosl; stosb");
+ /* 7 bytes */
+ if (count == 5*4 + 2) small_store("stosl; stosl; stosl; stosl; stosl; stosw");
+ /* 8 bytes, but oh well... */
+ if (count == 5*4 + 3) small_store("stosl; stosl; stosl; stosl; stosl; stosw; stosb");
+ /* 6 bytes */
+ if (count == 6*4 + 0) small_store("stosl; stosl; stosl; stosl; stosl; stosl");
+ /* the rest would be 7+ bytes and is handled below instead */
+#undef small_store
+
+ /* Not small, but multiple-of-4 store.
+ * "mov <const>,%ecx; rep; stosl" sequence is 7 bytes */
+ __asm__ __volatile__(
+ " rep; stosl\n"
+ : "=&c" (ecx), "=&D" (edi)
+ : "a" (eax), "0" (count / 4), "1" (s)
+ : "memory"
+ );
+ return s;
+}
+#if 1 /* -51 bytes on shared i386 build with gcc 4.3.0 */
+#define memset(s, c, count) ( \
+ ( !(__builtin_constant_p(c) && __builtin_constant_p(count)) \
+ || ((count) > (6*4 + 0) && ((count) % 4) != 0) \
+ ) \
+ ? memset((s), (c), (count)) \
+ : inlined_memset_const_c_count4((s), (c), (count)) \
+ )
+#endif
+
+
+static __always_inline
+void *inlined_mempcpy_const_count4(void *d, const void *s, unsigned count)
+{
+ int ecx;
+ char *esi, *edi;
+
+ if (count == 0)
+ return d;
+
+ if (count == 1) {
+ *(char *)d = *(char *)s;
+ return d + 1;
+ }
+ if (count == 2) {
+ *(short *)d = *(short *)s;
+ return d + 2;
+ }
+ /* Small string moves: don't clobber ecx
+ * (clobbers only esi and edi) */
+#define small_move(arg) { \
+ __asm__ __volatile__( \
+ arg \
+ : "=&S" (esi), "=&D" (edi) \
+ : "0" (s), "1" (d) \
+ : "memory" \
+ ); \
+ return edi; \
+}
+ if (count == 3) small_move("movsw; movsb");
+ if (count == 1*4 + 0) {
+ *(int *)d = *(int *)s;
+ return d + 4;
+ }
+ if (count == 1*4 + 1) small_move("movsl; movsb");
+ if (count == 1*4 + 2) small_move("movsl; movsw");
+ if (count == 1*4 + 3) small_move("movsl; movsw; movsb");
+ if (count == 2*4 + 0) small_move("movsl; movsl");
+ if (count == 2*4 + 1) small_move("movsl; movsl; movsb");
+ if (count == 2*4 + 2) small_move("movsl; movsl; movsw");
+ if (count == 2*4 + 3) small_move("movsl; movsl; movsw; movsb");
+ if (count == 3*4 + 0) small_move("movsl; movsl; movsl");
+ if (count == 3*4 + 1) small_move("movsl; movsl; movsl; movsb");
+ if (count == 3*4 + 2) small_move("movsl; movsl; movsl; movsw");
+ if (count == 3*4 + 3) small_move("movsl; movsl; movsl; movsw; movsb");
+ if (count == 4*4 + 0) small_move("movsl; movsl; movsl; movsl");
+ if (count == 4*4 + 1) small_move("movsl; movsl; movsl; movsl; movsb");
+ /* going over 7 bytes is suboptimal */
+ /* movsw is 2-byte insn, so this one takes 6 bytes: */
+ if (count == 4*4 + 2) small_move("movsl; movsl; movsl; movsl; movsw");
+ /* 7 bytes */
+ if (count == 4*4 + 3) small_move("movsl; movsl; movsl; movsl; movsw; movsb");
+ /* 5 bytes */
+ if (count == 5*4 + 0) small_move("movsl; movsl; movsl; movsl; movsl");
+ /* 6 bytes */
+ if (count == 5*4 + 1) small_move("movsl; movsl; movsl; movsl; movsl; movsb");
+ /* 7 bytes */
+ if (count == 5*4 + 2) small_move("movsl; movsl; movsl; movsl; movsl; movsw");
+ /* 8 bytes, but oh well... */
+ if (count == 5*4 + 3) small_move("movsl; movsl; movsl; movsl; movsl; movsw; movsb");
+ /* 6 bytes */
+ if (count == 6*4 + 0) small_move("movsl; movsl; movsl; movsl; movsl; movsl");
+ /* the rest would be 7+ bytes and is handled below instead */
+#undef small_move
+
+ /* Not small, but multiple-of-4 move.
+ * "mov <const>,%ecx; rep; movsl" sequence is 7 bytes */
+ __asm__ __volatile__(
+ " rep; movsl\n"
+ : "=&c" (ecx), "=&S" (esi), "=&D" (edi)
+ : "0" (count / 4), "1" (s), "2" (d)
+ : "memory"
+ );
+ return edi;
+}
+static __always_inline
+void *inlined_memcpy_const_count4(void *d, const void *s, unsigned count)
+{
+ inlined_mempcpy_const_count4(d, s, count);
+ return d;
+}
+#if 1 /* +34 bytes on shared i386 build with gcc 4.3.0 */
+#define mempcpy(d, s, count) ( \
+ ( !(__builtin_constant_p(count)) \
+ || ((count) > (6*4 + 0) && ((count) % 4) != 0) \
+ ) \
+ ? mempcpy((d), (s), (count)) \
+ : inlined_mempcpy_const_count4((d), (s), (count)) \
+ )
+#define memcpy(d, s, count) ( \
+ ( !(__builtin_constant_p(count)) \
+ || ((count) > (6*4 + 0) && ((count) % 4) != 0) \
+ ) \
+ ? memcpy((d), (s), (count)) \
+ : inlined_memcpy_const_count4((d), (s), (count)) \
+ )
+#endif
+
+
+static __always_inline
+size_t inlined_strlen(const char *s)
+{
+ int edi;
+ int ecx;
+ __asm__ __volatile__(
+ " repne; scasb\n"
+ /* " notl %0\n" */
+ /* " decl %0\n" */
+ : "=c" (ecx), "=&D" (edi)
+ : "1" (s), "a" (0), "0" (0xffffffffu)
+ /* : no clobbers */
+ );
+ return -ecx - 1;
+}
+#if 0 /* +1108 bytes on shared i386 build with gcc 4.3.0 */
+#define strlen(s) inlined_strlen(s)
+#endif
+
+
+static __always_inline
+char *inlined_stpcpy(char *dest, const char *src)
+{
+ char *esi, *edi;
+ int eax;
+ __asm__ __volatile__(
+ "1: lodsb\n"
+ " stosb\n"
+ " testb %%al, %%al\n"
+ " jnz 1b\n"
+ : "=&S" (esi), "=&D" (edi), "=&a" (eax)
+ : "0" (src), "1" (dest)
+ : "memory"
+ );
+ return edi - 1;
+}
+static __always_inline
+char *inlined_strcpy(char *dest, const char *src)
+{
+ inlined_stpcpy(dest, src);
+ return dest;
+}
+#if 0 /* +562 bytes on shared i386 build with gcc 4.3.0 */
+#define stpcpy(dest, src) inlined_stpcpy(dest, src)
+#define strcpy(dest, src) inlined_strcpy(dest, src)
+#endif
+
+
+static __always_inline
+void *inlined_memchr(const void *s, int c, size_t count)
+{
+ void *edi;
+ int ecx;
+ /* Unfortunately, c gets loaded to %eax (wide insn), not %al */
+ __asm__ __volatile__(
+ " jecxz 1f\n"
+ " repne; scasb\n"
+ " leal -1(%%edi), %%edi\n"
+ " je 2f\n"
+ "1:\n"
+ " xorl %%edi, %%edi\n"
+ "2:\n"
+ : "=&D" (edi), "=&c" (ecx)
+ : "a" (c), "0" (s), "1" (count)
+ /* : no clobbers */
+ );
+ return edi;
+}
+static __always_inline
+void *inlined_memchr_const_c(const void *s, int c, size_t count)
+{
+ void *edi;
+ int ecx, eax;
+ __asm__ __volatile__(
+ " jecxz 1f\n"
+ " movb %4, %%al\n" /* const c to %%al */
+ " repne; scasb\n"
+ " leal -1(%%edi), %%edi\n"
+ " je 2f\n"
+ "1:\n"
+ " xorl %%edi, %%edi\n"
+ "2:\n"
+ : "=&D" (edi), "=&c" (ecx), "=&a" (eax)
+ : "0" (s), "i" (c), "1" (count)
+ /* : no clobbers */
+ );
+ return edi;
+}
+#if 1 /* +2 bytes on shared i386 build with gcc 4.3.0 */
+#define memchr(s, c, count) ( \
+ __builtin_constant_p(c) \
+ ? inlined_memchr_const_c(s, (c) & 0xff, count) \
+ : inlined_memchr(s, c, count) \
+ )
+#endif
+
+#endif /* _LIBC_STRING_i386_H */
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