1 files changed, 34 insertions, 0 deletions
diff --git a/src/lib/strcmp.s b/src/lib/strcmp.s
new file mode 100644
index 0000000..7e6d2af
--- /dev/null
+++ b/src/lib/strcmp.s
@@ -0,0 +1,34 @@
+# --------------------------------------------
+# FUNCTION: strcmp
+# PURPOSE : compares twos strings, and returns
+#           if they are equal
+# INPUTS  : rdi = address of first string
+#           rsi = address of second string
+# OUTPUTS : rax = 1 if equals else 0
+# CLOBBERS: 
+# --------------------------------------------
+.section .text
+.globl strcmp
+.type strcmp, @function
+strcmp:
+    xorq %rax, %rax                     # i = 0
+    movb (%rdi, %rax, 1), %r8b
+    movb (%rsi, %rax, 1), %r9b
+
+    cmpb %r8b, %r9b                     # compare each byte
+    jne .strcmp_fail
+
+    testb %r8b, %r8b                    # if any is null,
+    jz .strcmp_success                  # both are null here
+
+    incq %rax
+
+    jmp strcmp
+
+.strcmp_fail:
+    xorq %rax, %rax
+    ret
+
+.strcmp_success:
+    movq $1, %rax
+    ret