From 29de86703927170785c59fa2c55ecc5bb624ceb2 Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Mon, 26 Mar 2018 23:30:26 -0500
Subject: [PATCH] Fix bug causing functions with 254 bytes of locals to crash
 on return.

This was a bug with the code for moving the return address. It would generate a "LDA 0" instruction when it was trying to load the value at DP+256.

The following program (derived from a csmith-generated test case) demonstrates the crash:

#pragma optimize 8
int main (int argc, char **argv) {
    char s[0xFC];
}
---
 Gen.pas | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Gen.pas b/Gen.pas
index 7e39220..7f30571 100644
--- a/Gen.pas
+++ b/Gen.pas
@@ -5091,7 +5091,7 @@ procedure GenTree {op: icptr};
    {if anything needs to be removed from the stack, move the return val}
    size := localSize + parameterSize;
    if parameterSize <> 0 then begin
-      if localSize > 254 then begin
+      if localSize > 253 then begin
          GenNative(m_ldx_imm, immediate, localSize+1, nil, 0);
          GenNative(m_lda_dirx, direct, 0, nil, 0);
          GenNative(m_ldy_dirx, direct, 1, nil, 0);