From aa82c562dbbbdabac2acc43d5002bfe8b46ca646 Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Sat, 11 Apr 2026 16:30:26 -0400
Subject: strlen() => strlen8(), save a measly 4 bytes. 7597 bytes free.

---
 src/strlen8.s | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 src/strlen8.s

(limited to 'src/strlen8.s')

diff --git a/src/strlen8.s b/src/strlen8.s
new file mode 100644
index 0000000..c622d73
--- /dev/null
+++ b/src/strlen8.s
@@ -0,0 +1,24 @@
+ ; strlen() implementation that only looks at the first 256
+ ; byte of the string. returns 255 if the length is >=255.
+ ; saves a measly 4 bytes over the cc65 strlen().
+
+ ; extern unsigned char strlen8(const char *str);
+
+ .importzp ptr1
+ .export _strlen8
+
+_strlen8:
+ sta ptr1
+ stx ptr1+1
+ ldy #0
+@loop:
+ lda (ptr1),y
+ beq @done
+ iny
+ bne @loop
+ dey ; return(255) if Y rolls over
+@done:
+ tya
+ ldx #0 ; sadly necessary even though we return a char...
+ rts
+
-- 
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