1 files changed, 81 insertions, 0 deletions
diff --git a/zap/src/streq.c b/zap/src/streq.c
new file mode 100644
index 0000000..6425ef7
--- /dev/null
+++ b/zap/src/streq.c
@@ -0,0 +1,81 @@
+/*
+ Copyright 2022 Gabriel Jensen.
+ This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+ If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
+*/
+
+#include <zap/priv.h>
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#if defined(zap_priv_fastimpl)
+__asm__ (
+ ".global zap_streq\n"
+
+ "zap_streq:\n"
+ /*
+ char const * lstr
+ char const * rstr
+ */
+#if defined(sus_arch_amd64)
+ /* rax: Address of the current input character. */
+ "movq %rdi,%rax\n"
+ /* rsi: Address of the current output character. */
+ "movq %rsi,%rsi\n"
+ /* rdx: Current input character. */
+ /* rcx: Current output character. */
+ ".loop:\n"
+ "movb (%rax),%dl\n" /* Move the characters into registers. */
+ "movb (%rsi),%cl\n"
+ "cmpb %dl,%cl\n" /* Check if the characters are equal... */
+ "jne .neq\n" /* ... indicate inequality if they are not. */
+ "testb %dl,%dl\n" /* Check if we have reached the null-terminator... */
+ "jz .eq\n" /* ... indicate equality if we have. */
+ "incq %rax\n" /* Increment positions. */
+ "incq %rsi\n"
+ "jmp .loop\n" /* Restart loop. */
+ ".eq:\n" /* Indicate equality. */
+ "movb $0x1,%al\n"
+ "ret\n"
+ ".neq:\n" /* Indicate inequality. */
+ "movb $0x0,%al\n"
+ "ret\n"
+#elif defined(sus_arch_ia32)
+ /* eax: Address of the current input character. */
+ "movl 0x4(%esp),%eax\n"
+ /* ecx: Address of the current output character. */
+ "movl 0x8(%esp),%ecx\n"
+ /* edx: Current input character. */
+ /* edx: Current output character. */
+ ".loop:\n"
+ "movb (%eax),%dl\n" /* Move the characters into registers. */
+ "movb (%ecx),%dh\n"
+ "cmpb %dl,%dh\n" /* Check if the characters are equal... */
+ "jne .neq\n" /* ... indicate inequality if they are not. */
+ "testb %dl,%dl\n" /* Check if we have reached the null-terminator... */
+ "jz .eq\n" /* ... indicate equality if we have. */
+ "incl %eax\n" /* Increment positions. */
+ "incl %ecx\n"
+ "jmp .loop\n" /* Restart loop. */
+ ".eq:\n" /* Indicate equality. */
+ "movb $0x1,%al\n"
+ "ret\n"
+ ".neq:\n" /* Indicate inequality. */
+ "movb $0x0,%al\n"
+ "ret\n"
+#endif
+);
+#else
+bool zap_streq(char const * const _lstr,char const * const _rstr) {
+ char const * lpos = _lstr;
+ char const * rpos = _rstr;
+ for (;;++lpos,++rpos) {
+ char const lchr = *lpos;
+ char const rchr = *rpos;
+ sus_likely (lchr != rchr) {return false;}
+ if (lchr == '\x0') {return true;}
+ }
+ sus_unreach();
+}
+#endif