From b60c307ee6b90c4fcd5e9090e8c50952aa26377d Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Sun, 18 Feb 2024 21:01:01 -0600
Subject: [PATCH] Make strcat and strncat work properly when first string
 crosses a bank boundary.

Previously, the pointer was not properly updated to account for the bank crossing, so the characters from the second string would be written to the wrong bank.

Here is an example that illustrates this:

#include <memory.h>
#include <string.h>
#include <orca.h>
#include <stdio.h>
int main(void) {
        Handle hndl = NewHandle(0x1000f, userid(), 0xC000, 0);
        if (toolerror())
                return 0;
        char *s = *hndl;
        s = (void*)((unsigned long)s | 0xffff);
        strcpy(s, "foo");
        strcat(s, "bar");
        strncat(s, "baz", 5);
        puts(s);
}
---
 string.asm | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/string.asm b/string.asm
index e5cd5ae..6a06be5 100644
--- a/string.asm
+++ b/string.asm
@@ -616,7 +616,9 @@ lb2      long  M
          clc
          adc   s1
          sta   s1
-         short M                        copy characters 'til the null is found
+         bcc   lb2a
+         inc   s1+2
+lb2a     short M                        copy characters 'til the null is found
          ldy   #0
 lb3      lda   [s2],Y
          sta   [s1],Y
@@ -1013,7 +1015,9 @@ lb2      long  M
          clc
          adc   s1
          sta   s1
-         short M                        copy characters 'til the null is found
+         bcc   lb2a
+         inc   s1+2
+lb2a     short M                        copy characters 'til the null is found
          ldy   #0
          ldx   n
          beq   lb4