cmd/asm: fix the issue of moving 128-bit integers to vector registers on arm64

The CL 249758 added `FMOVQ $vcon, Vd` instruction and assembler used
128-bit simd literal-loading to load `$vcon` from pool into 128-bit vector
register `Vd`. Because Go does not have 128-bit integers for now, the
assembler will report an error of `immediate out of range` when
assembleing `FMOVQ $0x123456789abcdef0123456789abcdef, V0` instruction.

This patch lets 128-bit integers take two 64-bit operands, for the high
and low parts separately and adds `VMOVQ $hi, $lo, Vd` instruction to
move `$hi<<64+$lo' into 128-bit register `Vd`.

In addition, this patch renames `FMOVQ/FMOVD/FMOVS` ops to 'VMOVQ/VMOVD/VMOVS'
and uses them to move 128-bit, 64-bit and 32-bit constants into vector
registers, respectively

Update the go doc.

Fixes #40725

Change-Id: Ia3c83bb6463f104d2bee960905053a97299e0a3a
Reviewed-on: https://go-review.googlesource.com/c/go/+/255900
Trust: fannie zhang <Fannie.Zhang@arm.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

1 files changed, 11 insertions, 7 deletions

diff --git a/src/cmd/asm/internal/arch/arm64.go b/src/cmd/asm/internal/arch/arm64.go
index 3817fcd5c2..e643889aef 100644
--- a/src/cmd/asm/internal/arch/arm64.go
+++ b/src/cmd/asm/internal/arch/arm64.go
@@ -82,6 +82,17 @@ func IsARM64STLXR(op obj.As) bool {
 	return false
 }
 
+// IsARM64TBL reports whether the op (as defined by an arm64.A*
+// constant) is one of the TBL-like instructions and one of its
+// inputs does not fit into prog.Reg, so require special handling.
+func IsARM64TBL(op obj.As) bool {
+	switch op {
+	case arm64.AVTBL, arm64.AVMOVQ:
+		return true
+	}
+	return false
+}
+
 // ARM64Suffix handles the special suffix for the ARM64.
 // It returns a boolean to indicate success; failure means
 // cond was unrecognized.
@@ -125,13 +136,6 @@ func arm64RegisterNumber(name string, n int16) (int16, bool) {
 	return 0, false
 }
 
-// IsARM64TBL reports whether the op (as defined by an arm64.A*
-// constant) is one of the table lookup instructions that require special
-// handling.
-func IsARM64TBL(op obj.As) bool {
-	return op == arm64.AVTBL
-}
-
 // ARM64RegisterExtension parses an ARM64 register with extension or arrangement.
 func ARM64RegisterExtension(a *obj.Addr, ext string, reg, num int16, isAmount, isIndex bool) error {
 	Rnum := (reg & 31) + int16(num<<5)