duskos

commit c515797be0ac1bb903ddb86214d3985d5bbdeac7
parent 42f38fc09b312c97c826d7706efceb4fae41263a
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Tue,  6 Dec 2022 21:26:46 -0500

comp/c/vm/i386: fix integer promotion bug in logical ops

Diffstat:
M
fs/comp/c/vm/i386.fs
 | 
3
++-
M
fs/tests/comp/c/cc.fs
 | 
1
+
M
fs/tests/comp/c/test.c
 | 
8
++++++++

3 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/comp/c/vm/i386.fs b/fs/comp/c/vm/i386.fs
@@ -292,7 +292,8 @@ LOGOPCNT wordtbl _tblunsigned
 :w _ setz, ;       :w _ setnz, ;       'w _&&              'w _||
 
 : logop, ( opid -- )
-  vmop type typeunsigned? if _tblunsigned else _tblsigned then swap wexec ;
+  harmonizeops vmop type typeunsigned?
+  if _tblunsigned else _tblsigned then swap wexec ;
 
 : vm?:, ( condop -- )
   vmop :>res \ true op in reg
diff --git a/fs/tests/comp/c/cc.fs b/fs/tests/comp/c/cc.fs
@@ -105,6 +105,7 @@ opwidth4 14 #eq
 opwidth5 42 #eq
 opwidth6 1 #eq
 $ff 1 opwidth7 $1fe #eq
+opwidth8 0 #eq
 42 50 ptrari3 46 #eq
 41 value myval
 to' myval ptrari4 not #
diff --git a/fs/tests/comp/c/test.c b/fs/tests/comp/c/test.c
@@ -469,6 +469,14 @@ short opwidth6() {
 int opwidth7(char a, int b) {
 	return a << b;
 }
+// Under i386, integer promotion of a non-reg operand would result in a buggy
+// operation because we would read too much information from memory.
+int opwidth8() {
+	int x = 54;
+	globdata.baz[0] = 42;
+	globdata.baz[1] = 1;
+	return x < globdata.baz[0];
+}
 // when subtracting 2 pointers, the result is considered a scalar for the
 // remainder of the expression.
 int* ptrari3(int *lo, int *hi) {