From: ceriel <none@none>
Date: Mon, 16 Jul 1990 09:05:19 +0000 (+0000)
Subject: Fix: DIV and MOD on negative args
X-Git-Tag: release-5-5~1650
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=109a357e956927143d8372ee4683e9cd34850640;p=ack.git

Fix: DIV and MOD on negative args
---

diff --git a/lang/m2/comp/code.c b/lang/m2/comp/code.c
index f29a3f536..05ef6c1d6 100644
--- a/lang/m2/comp/code.c
+++ b/lang/m2/comp/code.c
@@ -782,7 +782,13 @@ CodeOper(expr, true_label, false_label)
 		Operands(expr);
 		switch(tp->tp_fund)	{
 		case T_INTEGER:
-			C_dvi(tp->tp_size);
+			if ((int)(tp->tp_size) == word_size) {
+			C_cal((int)(tp->tp_size) == (int)word_size 
+				? "dvi"
+				: "dvil");
+			}
+			C_asp(2*tp->tp_size);
+			C_lfr(tp->tp_size);
 			break;
 		case T_POINTER:
 		case T_EQUAL:
@@ -798,7 +804,13 @@ CodeOper(expr, true_label, false_label)
 		Operands(expr);
 		switch(tp->tp_fund)	{
 		case T_INTEGER:
-			C_rmi(tp->tp_size);
+			if ((int)(tp->tp_size) == word_size) {
+			C_cal((int)(tp->tp_size) == (int)word_size 
+				? "rmi"
+				: "rmil");
+			}
+			C_asp(2*tp->tp_size);
+			C_lfr(tp->tp_size);
 			break;
 		case T_POINTER:
 		case T_EQUAL:
diff --git a/lang/m2/comp/cstoper.c b/lang/m2/comp/cstoper.c
index 2cb9133ec..197e30258 100644
--- a/lang/m2/comp/cstoper.c
+++ b/lang/m2/comp/cstoper.c
@@ -186,35 +186,28 @@ cstibin(expp)
 			node_error(expp, "division by 0");
 			return;
 		}
-#if (-1)/2==0
-		o1 /= o2;
-#else
-		if (o1 == 0) break;
 		if ((o1 < 0) != (o2 < 0)) {
-			o1 = o1/o2 + 1;
+			if (o1 < 0) o1 = -o1;
+			else o2 = -o2;
+			o1 = -((o1+o2-1)/o2);
 		}
 		else {
 			o1 /= o2;
 		}
-#endif
 		break;
-
 	case MOD:
 		if (o2 == 0)	{
 			node_error(expp, "modulo by 0");
 			return;
 		}
-#if (-1)/2==0
-		o1 %= o2;
-#else
-		if (o1 == 0) break;
 		if ((o1 < 0) != (o2 < 0)) {
-			o1 -= (o1 / o2 + 1) * o2;
+			if (o1 < 0) o1 = -o1;
+			else o2 = -o2;
+			o1 = ((o1+o2-1)/o2) * o2 - o1;
 		}
 		else {
 			o1 %= o2;
 		}
-#endif
 		break;
 
 	case '+':
diff --git a/lang/m2/libm2/LIST b/lang/m2/libm2/LIST
index 5d8621cb0..4294f16a6 100644
--- a/lang/m2/libm2/LIST
+++ b/lang/m2/libm2/LIST
@@ -19,6 +19,7 @@ ArraySort.mod
 catch.c
 Traps.mod
 XXTermcap.c
+dvi.c
 Arguments.c
 LtoUset.e
 StrAss.c
diff --git a/lang/m2/libm2/dvi.c b/lang/m2/libm2/dvi.c
new file mode 100644
index 000000000..d72076def
--- /dev/null
+++ b/lang/m2/libm2/dvi.c
@@ -0,0 +1,68 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	implementation of DIV and MOD
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+  Reason:	We cannot use DVI and RMI, because DVI rounds towards 0
+		and Modula-2 requires truncation
+*/
+
+#include <em_abs.h>
+
+int
+dvi(j,i)
+	int j,i;
+{
+	if (j == 0) TRP(EIDIVZ);
+	if ((i < 0) != (j < 0)) {
+		if (i < 0) i = -i;
+		else j = -j;
+		return -((i+j-1)/j);
+	}
+	else return i/j;
+}
+
+long
+dvil(j,i)
+	long j,i;
+{
+	if (j == 0) TRP(EIDIVZ);
+	if ((i < 0) != (j < 0)) {
+		if (i < 0) i = -i;
+		else j = -j;
+		return -((i+j-1)/j);
+	}
+	else return i/j;
+}
+
+int
+rmi(j,i)
+	int j,i;
+{
+	if (j == 0) TRP(EIDIVZ);
+	if (i == 0) return 0;
+	if ((i < 0) != (j < 0)) {
+		if (i < 0) i = -i;
+		else j = -j;
+		return j*((i+j-1)/j)-i;
+	}
+	else return i%j;
+}
+
+long
+rmil(j,i)
+	long j,i;
+{
+	if (j == 0) TRP(EIDIVZ);
+	if (i == 0) return 0L;
+	if ((i < 0) != (j < 0)) {
+		if (i < 0) i = -i;
+		else j = -j;
+		return j*((i+j-1)/j)-i;
+	}
+	else return i%j;
+}