cmd/internal/obj/arm: support more ARM VFP instructions

Add support of more ARM VFP instructions in the assembler.
They were introduced in ARM VFPv2.

"NMULF/NMULD   Fm, Fn, Fd": Fd = -Fn*Fm
"MULAF/MULAD   Fm, Fn, Fd": Fd = Fd + Fn*Fm
"NMULAF/NMULAD Fm, Fn, Fd": Fd = -(Fd + Fn*Fm)
"MULSF/MULSD   Fm, Fn, Fd": Fd = Fd - Fn*Fm
"NMULSF/NMULSD Fm, Fn, Fd": Fd = -(Fd - Fn*Fm)

Change-Id: Icd302676ca44a9f5f153fce734225299403c4163
Reviewed-on: https://go-review.googlesource.com/60170
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/asm/internal/asm/testdata/armerror.s

@@ -35,6 +35,14 @@ TEXT errors(SB),$0
 	BL	4(R4)              // ERROR "non-zero offset"
 	ADDF	F0, R1, F2         // ERROR "illegal combination"
 	SWI	(R0)               // ERROR "illegal combination"
+	MULAD	F0, F1             // ERROR "illegal combination"
+	MULAF	F0, F1             // ERROR "illegal combination"
+	MULSD	F0, F1             // ERROR "illegal combination"
+	MULSF	F0, F1             // ERROR "illegal combination"
+	NMULAD	F0, F1             // ERROR "illegal combination"
+	NMULAF	F0, F1             // ERROR "illegal combination"
+	NMULSD	F0, F1             // ERROR "illegal combination"
+	NMULSF	F0, F1             // ERROR "illegal combination"
 	NEGF	F0, F1, F2         // ERROR "illegal combination"
 	NEGD	F0, F1, F2         // ERROR "illegal combination"
 	ABSF	F0, F1, F2         // ERROR "illegal combination"

src/cmd/asm/internal/asm/testdata/armv6.s

@@ -18,6 +18,18 @@ TEXT	foo(SB), DUPOK|NOSPLIT, $0
 	MULD.EQ	F3, F4, F5    // 035b240e
 	MULF.NE	F0, F2        // 002a221e
 	MULD	F3, F5        // 035b25ee
+	NMULF	F0, F1, F2    // 402a21ee
+	NMULF	F3, F7        // 437a27ee
+	NMULD	F0, F1, F2    // 402b21ee
+	NMULD	F3, F7        // 437b27ee
+	MULAF	F5, F6, F7    // 057a06ee
+	MULAD	F5, F6, F7    // 057b06ee
+	MULSF	F5, F6, F7    // 457a06ee
+	MULSD	F5, F6, F7    // 457b06ee
+	NMULAF	F5, F6, F7    // 057a16ee
+	NMULAD	F5, F6, F7    // 057b16ee
+	NMULSF	F5, F6, F7    // 457a16ee
+	NMULSD	F5, F6, F7    // 457b16ee
 	DIVF	F0, F1, F2    // 002a81ee
 	DIVD.EQ	F3, F4, F5    // 035b840e
 	DIVF.NE	F0, F2        // 002a821e

src/cmd/internal/obj/arm/a.out.go

@@ -230,6 +230,16 @@ const (
 	ASUBD
 	AMULF
 	AMULD
+	ANMULF
+	ANMULD
+	AMULAF
+	AMULAD
+	ANMULAF
+	ANMULAD
+	AMULSF
+	AMULSD
+	ANMULSF
+	ANMULSD
 	ADIVF
 	ADIVD
 	ASQRTF

src/cmd/internal/obj/arm/anames.go

@@ -53,6 +53,16 @@ var Anames = []string{
 	"SUBD",
 	"MULF",
 	"MULD",
+	"NMULF",
+	"NMULD",
+	"MULAF",
+	"MULAD",
+	"NMULAF",
+	"NMULAD",
+	"MULSF",
+	"MULSD",
+	"NMULSF",
+	"NMULSD",
 	"DIVF",
 	"DIVD",
 	"SQRTF",

src/cmd/internal/obj/arm/asm5.go

@@ -1651,6 +1651,16 @@ func buildop(ctxt *obj.Link) {
 			opset(ASUBD, r0)
 			opset(AMULF, r0)
 			opset(AMULD, r0)
+			opset(ANMULF, r0)
+			opset(ANMULD, r0)
+			opset(AMULAF, r0)
+			opset(AMULAD, r0)
+			opset(AMULSF, r0)
+			opset(AMULSD, r0)
+			opset(ANMULAF, r0)
+			opset(ANMULAD, r0)
+			opset(ANMULSF, r0)
+			opset(ANMULSD, r0)
 			opset(ADIVF, r0)
 			opset(ADIVD, r0)
 
@@ -2259,7 +2269,12 @@ func (c *ctxt5) asmout(p *obj.Prog, o *Optab, out []uint32) {
 		rt := int(p.To.Reg)
 		r := int(p.Reg)
 		if r == 0 {
-			r = rt
+			switch p.As {
+			case AMULAD, AMULAF, AMULSF, AMULSD, ANMULAF, ANMULAD, ANMULSF, ANMULSD:
+				c.ctxt.Diag("illegal combination: %v", p)
+			default:
+				r = rt
+			}
 		}
 
 		o1 |= (uint32(rf)&15)<<0 | (uint32(r)&15)<<16 | (uint32(rt)&15)<<12
@@ -2870,6 +2885,26 @@ func (c *ctxt5) oprrr(p *obj.Prog, a obj.As, sc int) uint32 {
 		return o | 0xe<<24 | 0x2<<20 | 0xb<<8 | 0<<4
 	case AMULF:
 		return o | 0xe<<24 | 0x2<<20 | 0xa<<8 | 0<<4
+	case ANMULD:
+		return o | 0xe<<24 | 0x2<<20 | 0xb<<8 | 0x4<<4
+	case ANMULF:
+		return o | 0xe<<24 | 0x2<<20 | 0xa<<8 | 0x4<<4
+	case AMULAD:
+		return o | 0xe<<24 | 0xb<<8
+	case AMULAF:
+		return o | 0xe<<24 | 0xa<<8
+	case AMULSD:
+		return o | 0xe<<24 | 0xb<<8 | 0x4<<4
+	case AMULSF:
+		return o | 0xe<<24 | 0xa<<8 | 0x4<<4
+	case ANMULAD:
+		return o | 0xe<<24 | 0x1<<20 | 0xb<<8
+	case ANMULAF:
+		return o | 0xe<<24 | 0x1<<20 | 0xa<<8
+	case ANMULSD:
+		return o | 0xe<<24 | 0x1<<20 | 0xb<<8 | 0x4<<4
+	case ANMULSF:
+		return o | 0xe<<24 | 0x1<<20 | 0xa<<8 | 0x4<<4
 	case ADIVD:
 		return o | 0xe<<24 | 0x8<<20 | 0xb<<8 | 0<<4
 	case ADIVF: