6l, 8l: handle forward JCXZ

R=rsc
CC=golang-dev, vcc.163
https://golang.org/cl/4963044

diff --git a/src/cmd/6l/span.c b/src/cmd/6l/span.c
index 5d13ad44b265a0653f1b91f6c79893fe11da4b47..7313e42b2f0b817e80f4dfa0407c42c34a376161 100644 (file)
--- a/src/cmd/6l/span.c
+++ b/src/cmd/6l/span.c
@@ -1439,10 +1439,11 @@ found:
 
        case Zbr:
        case Zjmp:
+       case Zloop:
                // TODO: jump across functions needs reloc
                q = p->pcond;
                if(q == nil) {
-                       diag("jmp/branch without target");
+                       diag("jmp/branch/loop without target");
                        errorexit();
                }
                if(q->as == ATEXT) {
@@ -1468,6 +1469,8 @@ found:
                        if(v >= -128) {
                                *andptr++ = op;
                                *andptr++ = v;
+                       } else if(t[2] == Zloop) {
+                               diag("loop too far: %P", p);
                        } else {
                                v -= 5-2;
                                if(t[2] == Zbr) {
@@ -1489,6 +1492,8 @@ found:
                if(p->back & 2) { // short
                        *andptr++ = op;
                        *andptr++ = 0;
+               } else if(t[2] == Zloop) {
+                       diag("loop too far: %P", p);
                } else {
                        if(t[2] == Zbr)
                                *andptr++ = 0x0f;
@@ -1520,19 +1525,6 @@ found:
 */
                break;
 
-       case Zloop:
-               q = p->pcond;
-               if(q == nil) {
-                       diag("loop without target");
-                       errorexit();
-               }
-               v = q->pc - p->pc - 2;
-               if(v < -128 && v > 127)
-                       diag("loop too far: %P", p);
-               *andptr++ = op;
-               *andptr++ = v;
-               break;
-
        case Zbyte:
                v = vaddr(&p->from, &rel);
                if(rel.siz != 0) {

diff --git a/src/cmd/8l/span.c b/src/cmd/8l/span.c
index a4cba125763ca1a34a24ae84ca5d939f7f094851..cc0069c683d128bad0366e273d907777126805d4 100644 (file)
--- a/src/cmd/8l/span.c
+++ b/src/cmd/8l/span.c
@@ -1056,9 +1056,10 @@ found:
 
        case Zbr:
        case Zjmp:
+       case Zloop:
                q = p->pcond;
                if(q == nil) {
-                       diag("jmp/branch without target");
+                       diag("jmp/branch/loop without target");
                        errorexit();
                }
                if(q->as == ATEXT) {
@@ -1086,6 +1087,8 @@ found:
                        if(v >= -128) {
                                *andptr++ = op;
                                *andptr++ = v;
+                       } else if(t[2] == Zloop) {
+                               diag("loop too far: %P", p);
                        } else {
                                v -= 5-2;
                                if(t[2] == Zbr) {
@@ -1107,6 +1110,8 @@ found:
                if(p->back & 2) { // short
                        *andptr++ = op;
                        *andptr++ = 0;
+               } else if(t[2] == Zloop) {
+                       diag("loop too far: %P", p);
                } else {
                        if(t[2] == Zbr)
                                *andptr++ = 0x0f;
@@ -1132,19 +1137,6 @@ found:
                put4(0);
                break;
 
-       case Zloop:
-               q = p->pcond;
-               if(q == nil) {
-                       diag("loop without target");
-                       errorexit();
-               }
-               v = q->pc - p->pc - 2;
-               if(v < -128 && v > 127)
-                       diag("loop too far: %P", p);
-               *andptr++ = op;
-               *andptr++ = v;
-               break;
-
        case Zbyte:
                v = vaddr(&p->from, &rel);
                if(rel.siz != 0) {