1 files changed, 77 insertions, 0 deletions
diff --git a/zap/src/fndbyte.c b/zap/src/fndbyte.c
new file mode 100644
index 0000000..85fc14d
--- /dev/null
+++ b/zap/src/fndbyte.c
@@ -0,0 +1,77 @@
+/*
+ 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 <stddef.h>
+#include <stdint.h>
+
+#if defined(zap_priv_fastimpl)
+__asm__ (
+ ".global zap_fndbyte\n"
+
+ "zap_fndbyte:\n"
+ /*
+ void const * ptr
+ size_t num
+ uint_least8_t byte
+ */
+#if defined(sus_arch_amd64)
+ /* rax: Address of the current element. */
+ "movq %rdi,%rax\n"
+ /* rsi: Address of the element after the last element. */
+ "addq %rdi,%rsi\n"
+ /* rcx: Current element. */
+ ".loop:\n"
+ "cmpq %rax,%rsi\n"
+ "je .nfnd\n" /* We have went through the entire array without finding the byte. */
+ "movb (%rax),%cl\n"
+ "cmpb %cl,%dl\n"
+ "je .fnd\n" /* We have found the byte. */
+ "incq %rax\n"
+ "jmp .loop\n"
+ ".fnd:\n"
+ "subq %rdi,%rax\n"
+ "ret\n"
+ ".nfnd:\n"
+ "movq $0xFFFFFFFFFFFFFFFF,%rax\n"
+ "ret\n"
+#elif defined(sus_arch_ia32)
+ /* eax: Address of the current element. */
+ "movl 0x4(%esp),%eax\n"
+ /* ecx: Address of the element after the last element. */
+ "movl 0x8(%esp),%ecx\n"
+ "addl %eax,%ecx\n"
+ /* edx: Byte value. */
+ "movb 0xC(%esp),%dl\n"
+ /* ebx: Current element. */
+ "pushl %ebx\n"
+ ".loop:\n"
+ "cmpl %eax,%ecx\n"
+ "je .nfnd\n" /* We have went through the entire array without finding the byte. */
+ "movb (%eax),%bl\n"
+ "cmpb %bl,%dl\n"
+ "je .fnd\n" /* We have found the byte. */
+ "incl %eax\n"
+ "jmp .loop\n"
+ ".fnd:\n"
+ "popl %ebx\n"
+ "subl 0x4(%esp),%eax\n"
+ "ret\n"
+ ".nfnd:\n"
+ "popl %ebx\n"
+ "movl $0xFFFFFFFF,%eax\n"
+ "ret\n"
+#endif
+);
+#else
+size_t zap_fndbyte(void const * const _ptr,size_t const _num,uint_least8_t const _byte) {
+ uint_least8_t const * ptr = (uint_least8_t const *)_ptr;
+ uint_least8_t const * const afterbuf = ptr + _num;
+ for (;ptr != afterbuf;++ptr) {sus_unlikely (*ptr == _byte) {return ptr - (uint_least8_t const *)_ptr;}}
+ return zap_typlit_usz(-0x1);
+}
+#endif