From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Tue, 15 Jun 2021 05:22:02 +0000 (+1000)
Subject: make strncmp direction safe
X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=3615a7d1910cea3c791916293b06b757c2879be9;p=rrq%2Frrqforth.git

make strncmp direction safe
---

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