From f1816f6a1db537069e1f874b9730cf9262006de9 Mon Sep 17 00:00:00 2001
From: "yu.dongliang" <18588496441@163.com>
Date: Thu, 11 Dec 2025 20:53:27 +0800
Subject: [PATCH 1/1] asm 1 commit

---
 Makefile |  2 ++
 main.c   | 18 ++++++++++++++++++
 str.s    | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+)
 create mode 100644 Makefile
 create mode 100644 main.c
 create mode 100644 str.s

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..3a2ff19
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,2 @@
+all:
+	gcc main.c str.s
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..8dddeea
--- /dev/null
+++ b/main.c
@@ -0,0 +1,18 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+int asm_strcmp (const char* s1, const char* s2);
+int asm_strncmp(const char* s1, const char* s2, int n);
+
+int main(int argc, char* argv[])
+{
+	if (argc < 4) {
+		printf("usage: ./a.out s1 s2 n\n");
+		return -1;
+	}
+
+	printf("strcmp: %d, strncmp: %d\n",
+			asm_strcmp (argv[1], argv[2]),
+			asm_strncmp(argv[1], argv[2], atoi(argv[3])));
+	return 0;
+}
diff --git a/str.s b/str.s
new file mode 100644
index 0000000..be69be8
--- /dev/null
+++ b/str.s
@@ -0,0 +1,56 @@
+.text
+.global asm_strncmp, asm_strcmp
+
+asm_strcmp:
+#rdi = s1
+#rsi = s2
+0:
+	movb (%rdi), %al
+	cmpb (%rsi), %al
+	jl   2f
+	jg   3f
+
+	test %al, %al
+	je   1f 
+
+	inc  %rsi
+	inc  %rdi
+	jmp  0b 
+1:
+	mov $0, %eax
+	ret
+2:
+	mov $-1, %eax
+	ret
+3:
+	mov $1, %eax
+	ret
+
+asm_strncmp:
+#rdi = s1
+#rsi = s2
+#edx = n
+0:
+	movb (%rdi), %al
+	cmpb (%rsi), %al
+	jl   2f
+	jg   3f
+
+	test %al, %al
+	je   1f 
+
+	inc  %rsi
+	inc  %rdi
+	dec  %edx
+
+	test %edx, %edx
+	jne  0b
+1:
+	mov $0, %eax
+	ret
+2:
+	mov $-1, %eax
+	ret
+3:
+	mov $1, %eax
+	ret
-- 
2.25.1