cmd/internal/obj/arm64: fix encoding of condition

The current code treats condition as special register and write
its raw data directly into instruction.

The fix converts the raw data into correct condition encoding.
Also fix the operand catogery of FCCMP.

Add tests to cover all cases.

Change-Id: Ib194041bd9017dd0edbc241564fe983082ac616b
Reviewed-on: https://go-review.googlesource.com/41511
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/cmd/asm/internal/asm/testdata/arm64.s

@@ -156,7 +156,7 @@ again:
 //	{
 //		outcode($1, &$2, NREG, &$4);
 //	}
-	CSET	GT, R1
+	CSET	GT, R1	// e1d79f9a
 //
 // CSEL/CSINC/CSNEG/CSINV
 //
@@ -164,16 +164,18 @@ again:
 //	{
 //		outgcode($1, &$2, $6.reg, &$4, &$8);
 //	}
-	CSEL	LT, R1, R2, ZR
-	CSINC	GT, R1, ZR, R3
-	CSNEG	MI, R1, R2, R3
-	CSINV	CS, R1, R2, R3 // CSINV HS, R1, R2, R3
+	CSEL	LT, R1, R2, ZR	// 3fb0829a
+	CSINC	GT, R1, ZR, R3	// 23c49f9a
+	CSNEG	MI, R1, R2, R3	// 234482da
+	CSINV	CS, R1, R2, R3	// CSINV HS, R1, R2, R3 // 232082da
 
 //		LTYPES cond ',' reg ',' reg
 //	{
 //		outcode($1, &$2, $4.reg, &$6);
 //	}
-	CSEL	LT, R1, R2
+	CINC	EQ, R4, R9	// 8914849a
+	CINV	PL, R11, R22	// 76418bda
+	CNEG	LS, R13, R7	// a7858dda
 //
 // CCMN
 //
@@ -181,7 +183,7 @@ again:
 //	{
 //		outgcode($1, &$2, $6.reg, &$4, &$8);
 //	}
-	CCMN	MI, ZR, R1, $4
+	CCMN	MI, ZR, R1, $4	// e44341ba
 
 //
 // FADDD
@@ -217,7 +219,7 @@ again:
 //	{
 //		outgcode($1, &$2, $6.reg, &$4, &$8);
 //	}
-//	FCCMP	LT, F1, F2, $1
+	FCCMPS	LT, F1, F2, $1	// 41b4211e
 
 //
 // FMULA

src/cmd/internal/obj/arm64/asm7.go

@@ -495,7 +495,7 @@ var optab = []Optab{
 	{AFMOVD, C_FREG, C_NONE, C_REG, 29, 4, 0, 0, 0},
 	{AFCMPS, C_FREG, C_FREG, C_NONE, 56, 4, 0, 0, 0},
 	{AFCMPS, C_FCON, C_FREG, C_NONE, 56, 4, 0, 0, 0},
-	{AFCCMPS, C_COND, C_REG, C_VCON, 57, 4, 0, 0, 0},
+	{AFCCMPS, C_COND, C_FREG, C_VCON, 57, 4, 0, 0, 0},
 	{AFCSELD, C_COND, C_REG, C_FREG, 18, 4, 0, 0, 0},
 	{AFCVTSD, C_FREG, C_NONE, C_FREG, 29, 4, 0, 0, 0},
 	{ACLREX, C_NONE, C_NONE, C_VCON, 38, 4, 0, 0, 0},
@@ -2224,6 +2224,12 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
 		o1 = c.oprrr(p, p.As)
 
 		cond := int(p.From.Reg)
+		if cond < COND_EQ || cond > COND_NV {
+			c.ctxt.Diag("invalid condition\n%v", p)
+		} else {
+			cond -= COND_EQ
+		}
+
 		r := int(p.Reg)
 		var rf int
 		if r != 0 {
@@ -2246,12 +2252,17 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
 		}
 
 		rt := int(p.To.Reg)
-		o1 |= (uint32(rf&31) << 16) | (uint32(cond&31) << 12) | (uint32(r&31) << 5) | uint32(rt&31)
+		o1 |= (uint32(rf&31) << 16) | (uint32(cond&15) << 12) | (uint32(r&31) << 5) | uint32(rt&31)
 
 	case 19: /* CCMN cond, (Rm|uimm5),Rn, uimm4 -> ccmn Rn,Rm,uimm4,cond */
 		nzcv := int(p.To.Offset)
 
 		cond := int(p.From.Reg)
+		if cond < COND_EQ || cond > COND_NV {
+			c.ctxt.Diag("invalid condition\n%v", p)
+		} else {
+			cond -= COND_EQ
+		}
 		var rf int
 		if p.From3.Type == obj.TYPE_REG {
 			o1 = c.oprrr(p, p.As)
@@ -2261,7 +2272,7 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
 			rf = int(p.From3.Offset & 0x1F)
 		}
 
-		o1 |= (uint32(rf&31) << 16) | (uint32(cond) << 12) | (uint32(p.Reg&31) << 5) | uint32(nzcv)
+		o1 |= (uint32(rf&31) << 16) | (uint32(cond&15) << 12) | (uint32(p.Reg&31) << 5) | uint32(nzcv)
 
 	case 20: /* movT R,O(R) -> strT */
 		v := int32(c.regoff(&p.To))
@@ -2794,6 +2805,12 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
 		o1 = c.oprrr(p, p.As)
 
 		cond := int(p.From.Reg)
+		if cond < COND_EQ || cond > COND_NV {
+			c.ctxt.Diag("invalid condition\n%v", p)
+		} else {
+			cond -= COND_EQ
+		}
+
 		nzcv := int(p.To.Offset)
 		if nzcv&^0xF != 0 {
 			c.ctxt.Diag("implausible condition\n%v", p)
@@ -2804,7 +2821,7 @@ func (c *ctxt7) asmout(p *obj.Prog, o *Optab, out []uint32) {
 			break
 		}
 		rt := int(p.From3.Reg)
-		o1 |= uint32(rf&31)<<16 | uint32(cond)<<12 | uint32(rt&31)<<5 | uint32(nzcv)
+		o1 |= uint32(rf&31)<<16 | uint32(cond&15)<<12 | uint32(rt&31)<<5 | uint32(nzcv)
 
 	case 58: /* ldar/ldxr/ldaxr */
 		o1 = c.opload(p, p.As)