cmd/asm, math: add s390x floating point test instructions

Floating point test instructions allow special cases (NaN, ±∞ and
a few other useful properties) to be checked directly.

This CL adds the following instructions to the assembler:
 * LTEBR - load and test (float32)
 * LTDBR - load and test (float64)
 * TCEB  - test data class (float32)
 * TCDB  - test data class (float64)

Note that I have only added immediate versions of the 'test data
class' instructions for now as that's the only case I think the
compiler will use.

Change-Id: I3398aab2b3a758bf909bd158042234030c8af582
Reviewed-on: https://go-review.googlesource.com/104457Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/asm/internal/asm/testdata/s390x.s

@@ -304,6 +304,10 @@ TEXT main·foo(SB),DUPOK|NOSPLIT,$16-0 // TEXT main.foo(SB), DUPOK|NOSPLIT, $16-
 	LPDFR	F1, F2                 // b3700021
 	LNDFR	F3, F4                 // b3710043
 	CPSDR	F5, F6, F7             // b3725076
+	LTEBR	F1, F2                 // b3020021
+	LTDBR	F3, F4                 // b3120043
+	TCEB	F5, $8                 // ed5000080010
+	TCDB	F15, $4095             // edf00fff0011
 
 	VL	(R15), V1               // e710f0000006
 	VST	V1, (R15)               // e710f000000e

src/cmd/internal/obj/s390x/a.out.go

@@ -318,6 +318,10 @@ const (
 	AFIEBR
 	AFIDBR
 	ACPSDR
+	ALTEBR
+	ALTDBR
+	ATCEB
+	ATCDB
 
 	// move from GPR to FPR and vice versa
 	ALDGR

src/cmd/internal/obj/s390x/anames.go

@@ -90,6 +90,10 @@ var Anames = []string{
 	"FIEBR",
 	"FIDBR",
 	"CPSDR",
+	"LTEBR",
+	"LTDBR",
+	"TCEB",
+	"TCDB",
 	"LDGR",
 	"LGDR",
 	"CEFBRA",

src/cmd/internal/obj/s390x/asmz.go

@@ -213,6 +213,8 @@ var optab = []Optab{
 	Optab{ACFEBRA, C_FREG, C_NONE, C_NONE, C_REG, 83, 0},
 	Optab{AFIEBR, C_SCON, C_FREG, C_NONE, C_FREG, 48, 0},
 	Optab{ACPSDR, C_FREG, C_FREG, C_NONE, C_FREG, 49, 0},
+	Optab{ALTDBR, C_FREG, C_NONE, C_NONE, C_FREG, 50, 0},
+	Optab{ATCDB, C_FREG, C_NONE, C_NONE, C_SCON, 51, 0},
 
 	// load symbol address (plus offset)
 	Optab{AMOVD, C_SYMADDR, C_NONE, C_NONE, C_REG, 19, 0},
@@ -994,6 +996,10 @@ func buildop(ctxt *obj.Link) {
 			opset(AMOVDLE, r)
 			opset(AMOVDLT, r)
 			opset(AMOVDNE, r)
+		case ALTDBR:
+			opset(ALTEBR, r)
+		case ATCDB:
+			opset(ATCEB, r)
 		case AVL:
 			opset(AVLLEZB, r)
 			opset(AVLLEZH, r)
@@ -3298,6 +3304,27 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 	case 49: // copysign
 		zRRF(op_CPSDR, uint32(p.From.Reg), 0, uint32(p.To.Reg), uint32(p.Reg), asm)
 
+	case 50: // load and test
+		var opcode uint32
+		switch p.As {
+		case ALTEBR:
+			opcode = op_LTEBR
+		case ALTDBR:
+			opcode = op_LTDBR
+		}
+		zRRE(opcode, uint32(p.To.Reg), uint32(p.From.Reg), asm)
+
+	case 51: // test data class (immediate only)
+		var opcode uint32
+		switch p.As {
+		case ATCEB:
+			opcode = op_TCEB
+		case ATCDB:
+			opcode = op_TCDB
+		}
+		d2 := c.regoff(&p.To)
+		zRXE(opcode, uint32(p.From.Reg), 0, 0, uint32(d2), 0, asm)
+
 	case 67: // fmov $0 freg
 		var opcode uint32
 		switch p.As {

src/math/acosh_s390x.s

@@ -146,7 +146,7 @@ L10:
 	FMOVD	F0, F8
 	FMOVD	0(R9), F0
 	FMADD	F8, F8, F0
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	FSQRT	F0, F10
 L4:
 	WFADB	V10, V8, V0

src/math/asinh_s390x.s

@@ -84,7 +84,7 @@ L3:
 	BYTE	$0xFF
 	CMPW	R1, R2
 	BGT	L1
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	FMOVD	F0, F10
 	BLTU	L15
 L9:
@@ -120,13 +120,13 @@ L1:
 	FMOVD	F0, ret+8(FP)
 	RET
 L14:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L17
 	FMOVD	F0, F10
 L4:
 	FMOVD	192(R9), F2
 	WFMADB	V0, V0, V2, V0
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	FSQRT	F0, F8
 L5:
 	WFADB	V8, V10, V0

src/math/atan2_s390x.s

@@ -212,10 +212,10 @@ L3:
 	WFMADB	V4, V1, V3, V4
 	BLT	L18
 	BGT	L7
-	WORD	$0xB3120022	//ltdbr	%f2,%f2
+	LTDBR	F2, F2
 	BLTU	L21
 L8:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L22
 L9:
 	WFCHDBS	V2, V0, V0
@@ -238,11 +238,11 @@ L1:
 	RET
 
 L20:
-	WORD	$0xB3120022	//ltdbr	%f2,%f2
+	LTDBR	F2, F2
 	BLTU	L23
 	FMOVD	F2, F6
 L4:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L24
 	FMOVD	F0, F4
 L5:

src/math/cbrt_s390x.s

@@ -96,7 +96,7 @@ L1:
 	RET
 L3:
 L2:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BEQ	L1
 	FMOVD	F0, F2
 	WORD	$0xED209040	//mdb	%f2,.L10-.L9(%r9)

src/math/cosh_s390x.s

@@ -64,7 +64,7 @@ GLOBL coshe6<>+0(SB), RODATA, $8
 TEXT ·coshAsm(SB),NOSPLIT,$0-16
 	FMOVD   x+0(FP), F0
 	MOVD    $coshrodataL23<>+0(SB), R9
-	WORD    $0xB3120000     //ltdbr %f0,%f0
+	LTDBR	F0, F0
 	MOVD    $0x4086000000000000, R2
 	MOVD    $0x4086000000000000, R3
 	BLTU    L19

src/math/erfc_s390x.s

@@ -166,7 +166,7 @@ TEXT	·erfcAsm(SB), NOSPLIT, $0-16
 	RET
 
 L2:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	MOVH	$0x0, R4
 	BLTU	L3
 	FMOVD	F0, F1
@@ -264,7 +264,7 @@ L1:
 	FMOVD	F2, ret+8(FP)
 	RET
 L3:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L30
 	FMOVD	568(R9), F2
 	WFSDB	V0, V2, V0

src/math/exp_s390x.s

@@ -59,7 +59,7 @@ GLOBL ·exptexp<> + 0(SB), RODATA, $128
 TEXT	·expAsm(SB), NOSPLIT, $0-16
 	FMOVD	x+0(FP), F0
 	MOVD	$·exprodataL22<>+0(SB), R5
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L20
 	FMOVD	F0, F2
 L2:

src/math/expm1_s390x.s

@@ -64,7 +64,7 @@ GLOBL ·expm1tab<> + 0(SB), RODATA, $128
 TEXT	·expm1Asm(SB), NOSPLIT, $0-16
 	FMOVD	x+0(FP), F0
 	MOVD	$·expm1rodataL22<>+0(SB), R5
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L20
 	FMOVD	F0, F2
 L2:

src/math/log10_s390x.s

@@ -87,7 +87,7 @@ L1:
 	RET
 
 L2:
-	WORD    $0xB3120000     //ltdbr %f0,%f0
+	LTDBR	F0, F0
 	BLEU    L13
 	WORD    $0xED009080     //mdb %f0,.L20-.L19(%r9)
 	BYTE    $0x00

src/math/log_s390x.s

@@ -79,7 +79,7 @@ TEXT	·logAsm(SB), NOSPLIT, $0-16
 	BYTE	$0x59
 	MOVW	R1, R7
 	CMPBGT	R7, $22, L17
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	MOVD	$·logx43f<>+0(SB), R1
 	FMOVD	0(R1), F2
 	BLEU	L3
@@ -87,7 +87,7 @@ TEXT	·logAsm(SB), NOSPLIT, $0-16
 	MOVH	$0x8405, R0
 	BR	L15
 L7:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLEU	L3
 L15:
 	FMUL	F2, F0
@@ -161,7 +161,7 @@ L1:
 	FMOVD	F0, ret+8(FP)
 	RET
 L3:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BEQ	L20
 	BGE	L1
 	BVS	L1

src/math/pow_s390x.s

@@ -426,7 +426,7 @@ L1:
 	FMOVD	F1, ret+16(FP)
 	RET
 L43:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L44
 	FMOVD	F0, F3
 L7:
@@ -438,7 +438,7 @@ L7:
 L8:
 	WFCEDBS	V2, V2, V3
 	BVS	L9
-	WORD	$0xB3120022	//ltdbr	%f2,%f2
+	LTDBR	F2, F2
 	BEQ	L26
 	MOVW	R1, R6
 	CMPBLT	R6, $0, L45
@@ -469,7 +469,7 @@ L11:
 	BYTE	$0x1C
 	BR	L1
 L42:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L46
 	FMOVD	F0, F4
 L3:
@@ -534,7 +534,7 @@ L26:
 L34:
 	FMOVD	8(R9), F4
 L19:
-	WORD	$0xB3120066	//ltdbr	%f6,%f6
+	LTDBR	F6, F6
 	BLEU	L47
 L18:
 	WFMDB	V4, V5, V1
@@ -552,7 +552,7 @@ L5:
 L45:
 	WFCEDBS	V0, V0, V4
 	BVS	L35
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLEU	L48
 	FMOVD	8(R9), F4
 L12:
@@ -576,7 +576,7 @@ L48:
 	BYTE	$0x59
 	MOVW	R1, R6
 	CMPBEQ	R6, $0, L29
-	WORD	$0xB3120022	//ltdbr	%f2,%f2
+	LTDBR	F2, F2
 	BLTU	L50
 	FMOVD	F2, F4
 L14:
@@ -588,11 +588,11 @@ L14:
 	FSUB	F7, F3
 	WFCEDBS	V4, V3, V3
 	BEQ	L15
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	FMOVD	8(R9), F4
 	BNE	L16
 L13:
-	WORD	$0xB3120022	//ltdbr	%f2,%f2
+	LTDBR	F2, F2
 	BLT	L18
 L40:
 	FMOVD	$0, F0
@@ -615,7 +615,7 @@ L15:
 	BEQ	L32
 	FMOVD	0(R9), F4
 L17:
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BNE	L12
 	BR	L13
 L32:

src/math/sin_s390x.s

@@ -69,7 +69,7 @@ TEXT ·sinAsm(SB),NOSPLIT,$0-16
 	FMOVD   $(0.0), F1
 	FCMPU   F0, F1
 	BEQ     sinIsZero
-	WORD    $0xB3120000     //ltdbr %f0,%f0
+	LTDBR	F0, F0
 	BLTU    L17
 	FMOVD   F0, F5
 L2:
@@ -219,7 +219,7 @@ sinIsZero:
 
 TEXT ·cosAsm(SB),NOSPLIT,$0-16
 	FMOVD   x+0(FP), F0
-	WORD    $0xB3120000     //ltdbr %f0,%f0
+	LTDBR	F0, F0
 	BLTU    L35
 	FMOVD   F0, F1
 L21:

src/math/sinh_s390x.s

@@ -69,7 +69,7 @@ TEXT ·sinhAsm(SB),NOSPLIT,$0-16
 	BGT             sinhIsInf
 
 	MOVD    $sinhrodataL21<>+0(SB), R5
-	WORD    $0xB3120000     //ltdbr %f0,%f0
+	LTDBR	F0, F0
 	MOVD    sinhxinit<>+0(SB), R1
 	FMOVD   F0, F4
 	MOVD    R1, R3

src/math/tan_s390x.s

@@ -44,7 +44,7 @@ TEXT	·tanAsm(SB), NOSPLIT, $0-16
 	BEQ     atanIsZero
 
 	MOVD	$·tanrodataL13<>+0(SB), R5
-	WORD	$0xB3120000	//ltdbr	%f0,%f0
+	LTDBR	F0, F0
 	BLTU	L10
 	FMOVD	F0, F2
 L2:

src/math/tanh_s390x.s

@@ -64,7 +64,7 @@ TEXT ·tanhAsm(SB),NOSPLIT,$0-16
 	FCMPU   F0, F1
 	BEQ     tanhIsZero
 	MOVD    $tanhrodataL18<>+0(SB), R5
-	WORD    $0xB3120000     //ltdbr %f0,%f0
+	LTDBR	F0, F0
 	MOVD    $0x4034000000000000, R1
 	BLTU    L15
 	FMOVD   F0, F1