From 5f3cbbb8a499f6740b0992baa4fe68f1d018e6c5 Mon Sep 17 00:00:00 2001
From: Wesley Moore <wes@wezm.net>
Date: Thu, 6 Mar 2025 20:59:32 +1000
Subject: [PATCH] Implement streq routine
---
tests/harness.s | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/tests/harness.s b/tests/harness.s
index b6899fd..37b709e 100644
--- a/tests/harness.s
+++ b/tests/harness.s
@@ -55,3 +55,30 @@ read:
li a0, 0 # 0 = standard input (stdin)
ecall # invoke syscall
ret
+
+
+# Determine if two strings are equal
+# arguments:
+# a0: address of first string
+# a1: length of first string
+# a2: address of second string
+# a3: length of second string
+# return:
+# a0: 1 if equal, 0 otherwise
+streq:
+ bne a1, a2, 2f # If the lengths are not the same then the strings are different
+1:
+ beqz a1, 3f # If the remaining length is zero, string are the same
+ lbu a4, 0(a0) # load byte from string 1
+ lbu a5, 0(a2) # load byte from string 2
+ bne a4, a5, 2f # return false if bytes are not equal
+ addi a1, a1, -1 # decrement a1
+ addi a0, a0, 1 # go to next byte of string 1
+ addi a2, a2, 1 # go to next byte of string 2
+ j 1b # loop
+2:
+ li a0, 0 # 0 = false
+ ret
+3:
+ li a0, 1 # 1 = true
+ ret