From d512b6b8012c4bdbddc1dd81587bd8e0159e3d67 Mon Sep 17 00:00:00 2001
From: David Given <dg@cowlark.com>
Date: Wed, 17 Jan 2024 20:24:19 +0100
Subject: [PATCH] Fix incorrect casting of 16 bit to 32 bit signed values on
 the Z80. Add tests for this.

--HG--
branch : bazel
---
 src/cowbe/archz80.cow.ng |  2 +-
 tests/casts.good         |  8 ++++++++
 tests/casts.test.cow     | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/cowbe/archz80.cow.ng b/src/cowbe/archz80.cow.ng
index ffc07bf8..632dbeea 100644
--- a/src/cowbe/archz80.cow.ng
+++ b/src/cowbe/archz80.cow.ng
@@ -1881,7 +1881,7 @@ gen hlhl := CAST24(hl, sext==0)
 
 gen hlhl := CAST24(hl, sext!=0) uses a
 {
-	E_mov(REG_A, REG_L);
+	E_mov(REG_A, REG_H);
 	E_add(REG_A, REG_A);
 	E_sbc(REG_A, REG_A);
 	E_exx();
diff --git a/tests/casts.good b/tests/casts.good
index 10bf83d6..bcb1e87e 100644
--- a/tests/casts.good
+++ b/tests/casts.good
@@ -25,6 +25,10 @@ mone as uint8: yes
 mone as uint32: yes
 mone as int8: yes
 mone as int32: yes
+twohundred as uint8: yes
+twohundred as uint32: yes
+twohundred as int8: yes
+twohundred as int32: yes
 casts2
 one as uint8: yes
 one as uint32: yes
@@ -34,6 +38,10 @@ mone as uint8: yes
 mone as uint32: yes
 mone as int8: yes
 mone as int32: yes
+twohundred as uint8: yes
+twohundred as uint32: yes
+twohundred as int8: yes
+twohundred as int32: yes
 castu4
 one as uint8: yes
 one as uint16: yes
diff --git a/tests/casts.test.cow b/tests/casts.test.cow
index 03234c1e..e95c08dd 100644
--- a/tests/casts.test.cow
+++ b/tests/casts.test.cow
@@ -36,6 +36,7 @@ casts1();
 sub castu2() is
 	var one: uint16 := 1;
 	var mone: uint16 := -1;
+	var twohundred: uint16 := 200;
 
 	print("castu2\n");
 	print("one as uint8"); if (one as uint8) == 1 then yes(); else no(); end if;
@@ -46,12 +47,17 @@ sub castu2() is
 	print("mone as uint32"); if (mone as uint32) == 0xffff then yes(); else no(); end if;
 	print("mone as int8"); if (mone as int8) == -1 then yes(); else no(); end if;
 	print("mone as int32"); if (mone as int32) == 0xffff then yes(); else no(); end if;
+	print("twohundred as uint8"); if (twohundred as uint8) == 200 then yes(); else no(); end if;
+	print("twohundred as uint32"); if (twohundred as uint32) == 200 then yes(); else no(); end if;
+	print("twohundred as int8"); if (twohundred as int8) == 200 then yes(); else no(); end if;
+	print("twohundred as int32"); if (twohundred as int32) == 200 then yes(); else no(); end if;
 end sub;
 castu2();
 
 sub casts2() is
 	var one: int16 := 1;
 	var mone: int16 := -1;
+	var twohundred: int16 := 200;
 
 	print("casts2\n");
 	print("one as uint8"); if (one as uint8) == 1 then yes(); else no(); end if;
@@ -62,6 +68,10 @@ sub casts2() is
 	print("mone as uint32"); if (mone as uint32) == 0xffffffff then yes(); else no(); end if;
 	print("mone as int8"); if (mone as int8) == -1 then yes(); else no(); end if;
 	print("mone as int32"); if (mone as int32) == -1 then yes(); else no(); end if;
+	print("twohundred as uint8"); if (twohundred as uint8) == 200 then yes(); else no(); end if;
+	print("twohundred as uint32"); if (twohundred as uint32) == 200 then yes(); else no(); end if;
+	print("twohundred as int8"); if (twohundred as int8) == 200 then yes(); else no(); end if;
+	print("twohundred as int32"); if (twohundred as int32) == 200 then yes(); else no(); end if;
 end sub;
 casts2();