From: Russ Cox <rsc@golang.org>
Date: Mon, 10 Aug 2009 19:46:23 +0000 (-0700)
Subject: 8-bit div and mod
X-Git-Tag: weekly.2009-11-06~920
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=3f91f80a2173a636a6619cf65d09a451bdfcfcb5;p=gostls13.git

8-bit div and mod

R=ken
OCL=32975
CL=32975
---

diff --git a/src/cmd/6g/ggen.c b/src/cmd/6g/ggen.c
index 629a8cd3d1..278b2ef693 100644
--- a/src/cmd/6g/ggen.c
+++ b/src/cmd/6g/ggen.c
@@ -565,7 +565,7 @@ cgen_div(int op, Node *nl, Node *nr, Node *res)
 {
 	Node ax, dx, oldax, olddx;
 	Node n1, n2, n3, savl, savr;
-	int n, w, s;
+	int n, w, s, a;
 	Magic m;
 
 	if(nl->ullman >= UINF) {
@@ -616,8 +616,8 @@ cgen_div(int op, Node *nl, Node *nr, Node *res)
 	case 1:
 		// divide by 2
 		if(op == OMOD) {
-			if(issigned[nl->type->etype]) 
-				goto longdiv;
+			if(issigned[nl->type->etype])
+				goto longmod;
 			regalloc(&n1, nl->type, res);
 			cgen(nl, &n1);
 			nodconst(&n2, nl->type, 1);
@@ -641,8 +641,8 @@ cgen_div(int op, Node *nl, Node *nr, Node *res)
 		break;
 	default:
 		if(op == OMOD) {
-			if(issigned[nl->type->etype]) 
-				goto longdiv;
+			if(issigned[nl->type->etype])
+				goto longmod;
 			regalloc(&n1, nl->type, res);
 			cgen(nl, &n1);
 			nodconst(&n2, nl->type, mpgetfix(nr->val.u.xval)-1);
@@ -688,6 +688,7 @@ divbymul:
 	default:
 		goto longdiv;
 
+	case TUINT8:
 	case TUINT16:
 	case TUINT32:
 	case TUINT64:
@@ -709,6 +710,13 @@ divbymul:
 		gmove(&n2, &ax);			// const->ax
 
 		gins(optoas(OHMUL, nl->type), &n1, N);	// imul reg
+		if(w == 8) {
+			// fix up 8-bit multiply
+			Node ah, dl;
+			nodreg(&ah, types[TUINT8], D_AH);
+			nodreg(&dl, types[TUINT8], D_DL);
+			gins(AMOVB, &ah, &dl);
+		}
 
 		if(m.ua) {
 			// need to add numerator accounting for overflow
@@ -730,6 +738,7 @@ divbymul:
 		restx(&dx, &olddx);
 		return;
 
+	case TINT8:
 	case TINT16:
 	case TINT32:
 	case TINT64:
@@ -751,6 +760,13 @@ divbymul:
 		gmove(&n2, &ax);			// const->ax
 
 		gins(optoas(OHMUL, nl->type), &n1, N);	// imul reg
+		if(w == 8) {
+			// fix up 8-bit multiply
+			Node ah, dl;
+			nodreg(&ah, types[TUINT8], D_AH);
+			nodreg(&dl, types[TUINT8], D_DL);
+			gins(AMOVB, &ah, &dl);
+		}
 
 		if(m.sm < 0) {
 			// need to add numerator
@@ -795,13 +811,19 @@ longmod:
 	cgen(nl, &n1);
 	regalloc(&n2, nl->type, N);
 	cgen_div(ODIV, &n1, nr, &n2);
+	a = optoas(OMUL, nl->type);
+	if(w == 8) {
+		// use 2-operand 16-bit multiply
+		// because there is no 2-operand 8-bit multiply
+		a = AIMULW;
+	}
 	if(!smallintconst(nr)) {
 		regalloc(&n3, nl->type, N);
 		cgen(nr, &n3);
-		gins(optoas(OMUL, nl->type), &n3, &n2);
+		gins(a, &n3, &n2);
 		regfree(&n3);
 	} else
-		gins(optoas(OMUL, nl->type), nr, &n2);
+		gins(a, nr, &n2);
 	gins(optoas(OSUB, nl->type), &n2, &n1);
 	gmove(&n1, res);
 	regfree(&n1);
@@ -908,7 +930,7 @@ ret:
 /*
  * generate byte multiply:
  *	res = nl * nr
- * no byte multiply instruction so have to do
+ * no 2-operand byte multiply instruction so have to do
  * 16-bit multiply and take bottom half.
  */
 void
diff --git a/test/ken/divconst.go b/test/ken/divconst.go
index d0cbbbedcd..34d7d430b4 100644
--- a/test/ken/divconst.go
+++ b/test/ken/divconst.go
@@ -351,6 +351,114 @@ u16run()
 	}
 }
 
+func
+i8rand() int8
+{
+	for {
+		a := int8(rand.Uint32());
+		a >>= uint(rand.Intn(8));
+		if -a != a {
+			return a;
+		}
+	}
+	return 0;	// impossible
+}
+
+func
+i8test(a,b,c int8)
+{
+	d := a/c;
+	if d != b {
+		panicln("i8", a, b, c, d);
+	}
+}
+
+func
+i8run()
+{
+	var a, b int8;
+
+	for i:=0; i<Count; i++ {
+		a = i8rand();
+
+		b = a/1;	i8test(a,b,1);
+		b = a/2;	i8test(a,b,2);
+		b = a/3;	i8test(a,b,3);
+		b = a/4;	i8test(a,b,4);
+		b = a/5;	i8test(a,b,5);
+		b = a/6;	i8test(a,b,6);
+		b = a/7;	i8test(a,b,7);
+		b = a/8;	i8test(a,b,8);
+		b = a/10;	i8test(a,b,10);
+		b = a/8;	i8test(a,b,8);
+		b = a/20;	i8test(a,b,20);
+		b = a/32;	i8test(a,b,32);
+		b = a/60;	i8test(a,b,60);
+		b = a/64;	i8test(a,b,64);
+		b = a/127;	i8test(a,b,127);
+
+		b = a/-1;	i8test(a,b,-1);
+		b = a/-2;	i8test(a,b,-2);
+		b = a/-3;	i8test(a,b,-3);
+		b = a/-4;	i8test(a,b,-4);
+		b = a/-5;	i8test(a,b,-5);
+		b = a/-6;	i8test(a,b,-6);
+		b = a/-7;	i8test(a,b,-7);
+		b = a/-8;	i8test(a,b,-8);
+		b = a/-10;	i8test(a,b,-10);
+		b = a/-8;	i8test(a,b,-8);
+		b = a/-20;	i8test(a,b,-20);
+		b = a/-32;	i8test(a,b,-32);
+		b = a/-60;	i8test(a,b,-60);
+		b = a/-64;	i8test(a,b,-64);
+		b = a/-128;	i8test(a,b,-128);
+	}
+}
+
+func
+u8rand() uint8
+{
+	a := uint8(rand.Uint32());
+	a >>= uint(rand.Intn(8));
+	return a;
+}
+
+func
+u8test(a,b,c uint8)
+{
+	d := a/c;
+	if d != b {
+		panicln("u8", a, b, c, d);
+	}
+}
+
+func
+u8run()
+{
+	var a, b uint8;
+
+	for i:=0; i<Count; i++ {
+		a = u8rand();
+
+		b = a/1;	u8test(a,b,1);
+		b = a/2;	u8test(a,b,2);
+		b = a/3;	u8test(a,b,3);
+		b = a/4;	u8test(a,b,4);
+		b = a/5;	u8test(a,b,5);
+		b = a/6;	u8test(a,b,6);
+		b = a/7;	u8test(a,b,7);
+		b = a/8;	u8test(a,b,8);
+		b = a/10;	u8test(a,b,10);
+		b = a/8;	u8test(a,b,8);
+		b = a/20;	u8test(a,b,20);
+		b = a/32;	u8test(a,b,32);
+		b = a/60;	u8test(a,b,60);
+		b = a/64;	u8test(a,b,64);
+		b = a/128;	u8test(a,b,128);
+		b = a/184;	u8test(a,b,184);
+	}
+}
+
 func	xtest()
 
 func
@@ -363,6 +471,8 @@ main()
 	u32run();
 	i16run();
 	u16run();
+	i8run();
+	u8run();
 }
 
 func
diff --git a/test/ken/modconst.go b/test/ken/modconst.go
index 812a13ca82..7a9ebed0e4 100644
--- a/test/ken/modconst.go
+++ b/test/ken/modconst.go
@@ -351,6 +351,114 @@ u16run()
 	}
 }
 
+func
+i8rand() int8
+{
+	for {
+		a := int8(rand.Uint32());
+		a >>= uint(rand.Intn(8));
+		if -a != a {
+			return a;
+		}
+	}
+	return 0;	// impossible
+}
+
+func
+i8test(a,b,c int8)
+{
+	d := a%c;
+	if d != b {
+		panicln("i8", a, b, c, d);
+	}
+}
+
+func
+i8run()
+{
+	var a, b int8;
+
+	for i:=0; i<Count; i++ {
+		a = i8rand();
+
+		b = a%1;	i8test(a,b,1);
+		b = a%2;	i8test(a,b,2);
+		b = a%3;	i8test(a,b,3);
+		b = a%4;	i8test(a,b,4);
+		b = a%5;	i8test(a,b,5);
+		b = a%6;	i8test(a,b,6);
+		b = a%7;	i8test(a,b,7);
+		b = a%8;	i8test(a,b,8);
+		b = a%10;	i8test(a,b,10);
+		b = a%8;	i8test(a,b,8);
+		b = a%20;	i8test(a,b,20);
+		b = a%32;	i8test(a,b,32);
+		b = a%60;	i8test(a,b,60);
+		b = a%64;	i8test(a,b,64);
+		b = a%127;	i8test(a,b,127);
+
+		b = a%-1;	i8test(a,b,-1);
+		b = a%-2;	i8test(a,b,-2);
+		b = a%-3;	i8test(a,b,-3);
+		b = a%-4;	i8test(a,b,-4);
+		b = a%-5;	i8test(a,b,-5);
+		b = a%-6;	i8test(a,b,-6);
+		b = a%-7;	i8test(a,b,-7);
+		b = a%-8;	i8test(a,b,-8);
+		b = a%-10;	i8test(a,b,-10);
+		b = a%-8;	i8test(a,b,-8);
+		b = a%-20;	i8test(a,b,-20);
+		b = a%-32;	i8test(a,b,-32);
+		b = a%-60;	i8test(a,b,-60);
+		b = a%-64;	i8test(a,b,-64);
+		b = a%-128;	i8test(a,b,-128);
+		b = a%-101;	i8test(a,b,-101);
+	}
+}
+
+func
+u8rand() uint8
+{
+	a := uint8(rand.Uint32());
+	a >>= uint(rand.Intn(8));
+	return a;
+}
+
+func
+u8test(a,b,c uint8)
+{
+	d := a%c;
+	if d != b {
+		panicln("u8", a, b, c, d);
+	}
+}
+
+func
+u8run()
+{
+	var a, b uint8;
+
+	for i:=0; i<Count; i++ {
+		a = u8rand();
+
+		b = a%1;	u8test(a,b,1);
+		b = a%2;	u8test(a,b,2);
+		b = a%3;	u8test(a,b,3);
+		b = a%4;	u8test(a,b,4);
+		b = a%5;	u8test(a,b,5);
+		b = a%6;	u8test(a,b,6);
+		b = a%7;	u8test(a,b,7);
+		b = a%8;	u8test(a,b,8);
+		b = a%10;	u8test(a,b,10);
+		b = a%8;	u8test(a,b,8);
+		b = a%20;	u8test(a,b,20);
+		b = a%32;	u8test(a,b,32);
+		b = a%60;	u8test(a,b,60);
+		b = a%64;	u8test(a,b,64);
+		b = a%127;	u8test(a,b,127);
+	}
+}
+
 func	xtest()
 
 func
@@ -363,6 +471,8 @@ main()
 	u32run();
 	i16run();
 	u16run();
+	i8run();
+	u8run();
 }
 
 func