arm floating point simulation

R=rsc
CC=golang-dev
https://golang.org/cl/3565041

src/cmd/5l/softfloat.c

@@ -29,6 +29,11 @@ softfloat(void)
 				p->cond->mark |= LABEL;
 		for(p = cursym->text; p != P; p = p->link) {
 			switch(p->as) {
+			case AMOVW:
+				if(p->to.type == D_FREG || p->from.type == D_FREG)
+					goto soft;
+				goto notsoft;
+
 			case AMOVWD:
 			case AMOVWF:
 			case AMOVDW:
@@ -37,6 +42,7 @@ softfloat(void)
 			case AMOVDF:
 			case AMOVF:
 			case AMOVD:
+
 			case ACMPF:
 			case ACMPD:
 			case AADDF:
@@ -47,6 +53,12 @@ softfloat(void)
 			case AMULD:
 			case ADIVF:
 			case ADIVD:
+				goto soft;
+
+			default:
+				goto notsoft;
+
+			soft:
 				if (psfloat == P)
 					diag("floats used with _sfloat not defined");
 				if (!wasfloat || (p->mark&LABEL)) {
@@ -65,7 +77,8 @@ softfloat(void)
 					wasfloat = 1;
 				}
 				break;
-			default:
+
+			notsoft:
 				wasfloat = 0;
 			}
 		}

src/pkg/runtime/runtime.h

@@ -230,7 +230,9 @@ struct	M
 	uint32	machport;	// Return address for Mach IPC (OS X)
 	MCache	*mcache;
 	G*	lockedg;
-	uint64 freg[8];	// Floating point register storage used by ARM software fp routines
+	uint32	freglo[16];	// D[i] lsb and F[i]
+	uint32	freghi[16];	// D[i] msb and F[i+16]
+	uint32	fflag;		// floating point compare flags
 #ifdef __WINDOWS__
 	void*	gostack;	// bookmark to keep track of go stack during stdcall
 #endif