From 3615a7d1910cea3c791916293b06b757c2879be9 Mon Sep 17 00:00:00 2001
From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Tue, 15 Jun 2021 15:22:02 +1000
Subject: [PATCH] make strncmp direction safe

---
 wordlists.asm | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/wordlists.asm b/wordlists.asm
index 0ee7aec..1604168 100644
--- a/wordlists.asm
+++ b/wordlists.asm
@@ -88,12 +88,20 @@ p_strlen_LOOP:
 	pop rsi
 	cmp rcx,0
 	jle p_strncpy_END
-	cld
+	cmp rdi,rsi
+	je p_strncpy_END
+	jl p_strncpy_LOOP
+	;; copy down
+	std ; Direction is decrementing
+	add rdi,rcx
+	dec rdi
+	add rsi,rcx
+	dec rsi
 p_strncpy_LOOP:
+	rep
 	movsb
-	dec rcx
-	jg p_strncpy_LOOP
 p_strncpy_END:
+	cld ; Restore default direction as incrementing
 	popr rsi
 	next
 	
-- 
2.39.2