diff --git a/asm/encodable.go b/asm/encodable.go
index 2cf53a4..3ed5cd7 100644
--- a/asm/encodable.go
+++ b/asm/encodable.go
@@ -20,9 +20,9 @@ func Encodable(mnemonic string) bool {
 	switch upper {
 	case "RET", "NOP", "CALL", "JMP",
 		"POPFQ", "PUSHFQ", "INT", "LDMXCSR", "STMXCSR", "CMPSD", "SHA256RNDS2",
-		// The literal-data pseudo-ops, the accepted-and-ignored END and the
-		// SP adjust.
-		"BYTE", "WORD", "LONG", "QUAD", "END", "ADJSP":
+		// The literal-data pseudo-ops, the accepted-and-ignored END and
+		// bookkeeping statements, and the SP adjust.
+		"BYTE", "WORD", "LONG", "QUAD", "END", "ADJSP", "FUNCDATA", "PCDATA":
 		return true
 	}
 	if _, ok := noOperandTable[upper]; ok {
diff --git a/asm/evex.go b/asm/evex.go
index c139ba6..d38f3ab 100644
--- a/asm/evex.go
+++ b/asm/evex.go
@@ -737,6 +737,91 @@ var evexTable = map[string]evexSpec{
 	"VMOVLHPS": {1, 0x16, 0, 0, -1, vexNDS3, [3]int{8, 0, 0}},
 }
 
+// evexQuad describes one quad-register instruction: the opcode under
+// EVEX.0F38.W0 with the F2 mandatory prefix, and the width of the vector
+// registers the bracketed list and the destination take (512-bit ZMM for
+// the packed forms, 128-bit XMM for the scalar ones).
+type evexQuad struct {
+	opcode byte
+	width  int // register width in bytes: 64 (ZMM) or 16 (XMM)
+}
+
+// evexQuadTable maps the quad-register instructions (the 4FMAPS and 4VNNIW
+// families) to their encoding.  The operand shape is fixed: a single memory
+// source in r/m, the bracketed register list whose LOW register travels the
+// inverted 5-bit V'VVVV field, an optional opmask in aaa and the vector
+// destination in reg.  The vector length follows the destination (512-bit
+// for the ZMM list forms, 128-bit for the scalar ones) while the disp8×N
+// multiplier stays 16 for every member, the toolchain's own tuple choice.
+var evexQuadTable = map[string]evexQuad{
+	"V4FMADDPS":  {0x9A, 64},
+	"V4FMADDSS":  {0x9B, 16},
+	"V4FNMADDPS": {0xAA, 64},
+	"V4FNMADDSS": {0xAB, 16},
+	"VP4DPWSSD":  {0x52, 64},
+	"VP4DPWSSDS": {0x53, 64},
+}
+
+// isEvexQuad reports whether the mnemonic is a quad-register instruction.
+func isEvexQuad(upper string) bool {
+	_, ok := evexQuadTable[upper]
+	return ok
+}
+
+// encodeEvexQuad encodes the quad-register form: OP mem, [Zn-Zn+3], (K), dst.
+// The register list is the VVVV-side source: its low register fills the
+// inverted V'VVVV bits, which is why an indexed memory source above Z15 (no
+// spare EVEX.X bit once V' is taken) is refused.  Masking rides the standard
+// aaa field, zeroing keeps the usual requires-a-mask rule, and no other
+// suffix applies.
+func (e *enc) encodeEvexQuad(mnem string, q evexQuad, ops []Operand, sfx evexSuffix) error {
+	if len(ops) != 3 && len(ops) != 4 {
+		return fmt.Errorf("%s expects 3 or 4 operands (mem, [Zn-Zn+3], (K), dst), got %d", mnem, len(ops))
+	}
+	mem, lst := ops[0], ops[1]
+	dst := ops[len(ops)-1]
+	mask := 0
+	if len(ops) == 4 {
+		k, ok := ops[2].(Reg)
+		if !ok || !k.mask {
+			return fmt.Errorf("%s: third operand must be an opmask register", mnem)
+		}
+		if k.idx == 0 {
+			return fmt.Errorf("k0 is not a usable mask register")
+		}
+		mask = k.idx
+	}
+	list, ok := lst.(RegList)
+	if !ok {
+		return fmt.Errorf("%s: second operand must be a four-register list", mnem)
+	}
+	if list.Lo.size != q.width {
+		return fmt.Errorf("%s: the register list must hold %d-bit vector registers", mnem, q.width*8)
+	}
+	dstReg, ok := dst.(Reg)
+	if !ok || !dstReg.isVec() {
+		return fmt.Errorf("%s: destination must be a vector register", mnem)
+	}
+	if dstReg.size != q.width {
+		return fmt.Errorf("%s: the destination must be a %d-bit vector register", mnem, q.width*8)
+	}
+	if !memOperand(mem) {
+		return fmt.Errorf("%s: the source must be a memory operand", mnem)
+	}
+	// The list owns V'VVVV; a scaled index in the EVEX-only half would fold
+	// its fifth bit into the same field the list's low register occupies.
+	if m, ok := mem.(Mem); ok && m.HasIndex && m.Index.idx >= 16 {
+		return fmt.Errorf("%s: an index register above Z15 has no EVEX bit free", mnem)
+	}
+	if sfx.zeroing && mask == 0 {
+		return fmt.Errorf("%s: zeroing (.Z) requires a mask register", mnem)
+	}
+	spec := evexSpec{mapSel: 2, opcode: q.opcode, w: 0, pp: 3, opdigit: -1, n: [3]int{16, 16, 16}}
+	// The vector length follows the destination (512-bit for the ZMM forms,
+	// 128-bit for the scalar ones), exactly as the oracle encodes it.
+	return e.emitEvexFields(spec, dstReg.vecLenBit(), dstReg.idx, list.Lo.idx, mem, mask, sfx)
+}
+
 // evexBcastSpec describes an EVEX broadcast (VPBROADCASTD/Q): the opcode
 // depends on the source kind, a GPR source uses opReg, a memory source uses
 // opMem with a disp8×N of n.
@@ -812,8 +897,10 @@ func isEvex(mnemUpper string) bool {
 	if _, ok := evexBcastTable[mnemUpper]; ok {
 		return true
 	}
-	_, ok := evexMoveTable[mnemUpper]
-	return ok
+	if _, ok := evexMoveTable[mnemUpper]; ok {
+		return true
+	}
+	return isEvexQuad(mnemUpper)
 }
 
 // evexRequired reports whether the operands force the EVEX encoding of a
@@ -995,6 +1082,14 @@ func (e *enc) encodeEvex(mnemUpper string, ops []Operand, sfx evexSuffix) error
 		return e.encodeEvexRM(spec, ops, 0, sfx)
 	}
 	spec, inTable := evexTable[mnemUpper]
+	if q, ok := evexQuadTable[mnemUpper]; ok {
+		// The quad-register family carries no rounding, SAE or broadcast;
+		// only masking and zeroing apply.
+		if sfx.sae || sfx.bcst || sfx.rounding >= 0 {
+			return fmt.Errorf("%s takes no rounding/SAE/broadcast suffix", mnemUpper)
+		}
+		return e.encodeEvexQuad(mnemUpper, q, ops, sfx)
+	}
 	if inTable {
 		if (sfx.rounding >= 0 || sfx.sae) && !evexRound[mnemUpper] {
 			return fmt.Errorf("%s: rounding/SAE is not supported for this instruction", mnemUpper)
diff --git a/asm/operand.go b/asm/operand.go
index ac00558..a68bd39 100644
--- a/asm/operand.go
+++ b/asm/operand.go
@@ -14,6 +14,28 @@ type Imm int64
 
 func (Imm) isOperand() {}
 
+// RegList is a bracketed register range, [Z0-Z3]: the four-register source
+// of the 4FMAPS and 4VNNIW families.  The EVEX emit path carries the list's
+// low register through the inverted 5-bit V'VVVV field; the three higher
+// registers are implied by the instruction, so only the pair travels here.
+type RegList struct {
+	Lo Reg
+	Hi Reg // implied by the encoding; Lo.idx+3 by construction
+}
+
+func (RegList) isOperand() {}
+
+// FloatImm is a floating-point immediate ($-1.0).  The SSE mnemonics whose
+// encoding takes an XMM/memory source at that position rewrite it as a read
+// from a read-only pool constant ($f64.<hex> or $f32.<hex>), the toolchain's
+// own behaviour; every other instruction rejects it.
+type FloatImm struct {
+	Text string // the numeric text as written, sign excluded
+	Neg  bool   // a leading minus
+}
+
+func (FloatImm) isOperand() {}
+
 // Mem is a memory operand of the form disp(base)(index*scale).
 type Mem struct {
 	Base     Reg
diff --git a/testdata/verify/quadreg_amd64.s b/testdata/verify/quadreg_amd64.s
new file mode 100644
index 0000000..1896a13
--- /dev/null
+++ b/testdata/verify/quadreg_amd64.s
@@ -0,0 +1,44 @@
+// The quad-register instructions: the 4FMAPS family (V4FMADDPS,
+// V4FMADDSS, V4FNMADDPS, V4FNMADDSS) and the 4VNNIW pair (VP4DPWSSD,
+// VP4DPWSSDS).  The bracketed list's low register travels the inverted
+// V'VVVV field, the memory source keeps r/m, the opmask rides aaa and the
+// vector length follows the destination (512-bit for the ZMM forms,
+// 128-bit for the scalar ones) while the disp8xN multiplier stays 16 for
+// every member.  Every result is folded back so no instruction is dead.
+
+#include "textflag.h"
+
+// func quadf4(src *[16]uint32, n int) float32
+TEXT ·quadf4(SB), NOSPLIT, $0-20
+	MOVQ        src+0(FP), SI
+	MOVQ        n+8(FP), CX
+	// The packed 4-FMA form over four consecutive ZMM accumulators,
+	// masked with K2, K3 and unmasked alike; the displacements exercise
+	// the disp32 form and the disp8x16 compressed form.
+	V4FMADDPS   17(SI), [Z0-Z3], K2, Z0
+	V4FMADDPS   64(SI), [Z10-Z13], K2, Z1
+	V4FMADDPS   (SI), [Z20-Z23], Z2
+	V4FNMADDPS  96(SI), [Z1-Z4], K3, Z5
+	// The scalar form reads XMM lists and takes the 128-bit length; the
+	// displacement compresses by 16.
+	V4FMADDSS   7(AX), [X0-X3], K5, X22
+	V4FMADDSS   (DI), [X10-X13], K5, X23
+	V4FNMADDSS  16(SI), [X20-X23], K1, X24
+	// The 4-VNNI dot products, indexed source included.
+	VP4DPWSSD   15(DX)(BX*8), [Z2-Z5], K4, Z17
+	VP4DPWSSDS  -7(DI)(R8*1), [Z4-Z7], K1, Z31
+	VP4DPWSSD   (SI), [Z12-Z15], Z6
+	// Zeroing keeps the usual rule: a mask register must ride along.
+	V4FMADDPS.Z 128(SI), [Z24-Z27], K4, Z3
+	// Fold every accumulator into one scalar.
+	VPADDD      Z0, Z1, Z9
+	VPADDD      Z2, Z5, Z10
+	VPADDD      Z9, Z17, Z11
+	VPADDD      Z10, Z31, Z12
+	VPADDD      Z11, Z12, Z13
+	VPADDD      Z13, Z14, Z15
+	VADDSS      X22, X23, X0
+	VADDSS      X24, X0, X1
+	VADDSS      X1, X2, X3
+	VMOVSS      X3, ret+16(FP)
+	RET