1 files changed, 68 insertions, 0 deletions
diff --git a/rgo/src/fndchr.c b/rgo/src/fndchr.c
new file mode 100644
index 0000000..12cd006
--- /dev/null
+++ b/rgo/src/fndchr.c
@@ -0,0 +1,68 @@
+/*
+ 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 <rgo-priv.h>
+
+#if defined(rgo_priv_fastimpl)
+__asm__ (
+ ".global rgo_fndchr\n"
+
+ "rgo_fndchr:\n"
+ /*
+ char const * str
+ char chr
+ */
+#if defined(sus_arch_amd64)
+ /* rax: Address of the current character. */
+ "movq %rdi,%rax\n"
+ /* rdx: Current character. */
+ ".loop:\n"
+ "movb (%rax),%dl\n"
+ "cmpb %dl,%sil\n"
+ "je .fnd\n" /* Exit loop if we have found the character. */
+ "testb %dl,%dl\n"
+ "je .nfnd\n" /* We encountered the null-terminator but not the specified character. */
+ "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 character. */
+ "movl 0x4(%esp),%eax\n"
+ /* ecx: Character. */
+ "movb 0x8(%esp),%cl\n"
+ /* edx: Current character. */
+ ".loop:\n"
+ "movb (%eax),%dl\n"
+ "cmpb %dl,%cl\n"
+ "je .fnd\n" /* Exit loop if we have found the character. */
+ "testb %dl,%dl\n"
+ "je .nfnd\n" /* We encountered the null-terminator but not the specified character. */
+ "incl %eax\n"
+ "jmp .loop\n"
+ ".fnd:\n"
+ "subl 0x4(%esp),%eax\n"
+ "ret\n"
+ ".nfnd:\n"
+ "movl $0xFFFFFFFF,%eax\n"
+ "ret\n"
+#endif
+);
+#else
+sus_typ_usz rgo_fndchr(char const * const sus_restr _str,char const _chr) {
+ char const * sus_restr pos = _str;
+ for (;;++pos) {
+ char const chr = *pos;
+ sus_unlikely (chr == _chr) {return (sus_typ_usz)(pos - _str);}
+ sus_unlikely (chr == '\x0') {return sus_typlit_usz(-0x1);}
+ }
+ sus_unreach();
+}
+#endif