diff --git a/zstd/_generate/gen.go b/zstd/_generate/gen.go
index 40f573711e..755e6b46d7 100644
--- a/zstd/_generate/gen.go
+++ b/zstd/_generate/gen.go
@@ -287,12 +287,51 @@ func (o options) generateBody(name string, executeSingleTriple func(ctx *execute
 
 	// Update states, max tablelog 28
 	{
-		Comment("Update Literal Length State")
-		o.updateState(name+"_llState", llState, brValue, brBitsRead, "llTable")
-		Comment("Update Match Length State")
-		o.updateState(name+"_mlState", mlState, brValue, brBitsRead, "mlTable")
-		Comment("Update Offset State")
-		o.updateState(name+"_ofState", ofState, brValue, brBitsRead, "ofTable")
+		if o.bmi2 {
+			// Get total number of bits (it is safe, as nBits is <= 9, thus 3*9 < 255)
+			total := GP64()
+			LEAQ(Mem{Base: llState, Index: mlState, Scale: 1}, total)
+			ADDQ(ofState, total)
+			MOVBQZX(total.As8(), total) // total = llState.As8() + mlState.As8() + ofState.As8()
+
+			// Read `total` bits
+			bits := o.getBitsValue(name+"_getBits", total, brValue, brBitsRead)
+
+			// Update states
+			Comment("Update Offset State")
+			{
+				nBits := GP64()
+				lowBits := GP64()
+				MOVBQZX(ofState.As8(), nBits)
+				BZHIQ(nBits, bits, lowBits) // lowBits = bits & ((1 << nBits) - 1))
+				SHRXQ(nBits, bits, bits)    // bits >= nBits
+				o.nextState(name+"_ofState", ofState, lowBits, "ofTable")
+			}
+			Comment("Update Match Length State")
+			{
+				nBits := GP64()
+				lowBits := GP64()
+				MOVBQZX(mlState.As8(), nBits)
+				BZHIQ(nBits, bits, lowBits) // lowBits = lowBits & ((1 << nBits) - 1))
+				SHRXQ(nBits, bits, bits)    // lowBits >= nBits
+				o.nextState(name+"_mlState", mlState, lowBits, "mlTable")
+			}
+			Comment("Update Literal Length State")
+			{
+				nBits := GP64()
+				lowBits := GP64()
+				MOVBQZX(llState.As8(), nBits)
+				BZHIQ(nBits, bits, lowBits) // lowBits = lowBits & ((1 << nBits) - 1))
+				o.nextState(name+"_llState", llState, lowBits, "llTable")
+			}
+		} else {
+			Comment("Update Literal Length State")
+			o.updateState(name+"_llState", llState, brValue, brBitsRead, "llTable")
+			Comment("Update Match Length State")
+			o.updateState(name+"_mlState", mlState, brValue, brBitsRead, "mlTable")
+			Comment("Update Offset State")
+			o.updateState(name+"_ofState", ofState, brValue, brBitsRead, "ofTable")
+		}
 	}
 	Label(name + "_skip_update")
 
@@ -622,6 +661,39 @@ func (o options) updateState(name string, state, brValue, brBitsRead reg.GPVirtu
 	MOVQ(Mem{Base: tablePtr, Index: DX, Scale: 8}, state)
 }
 
+func (o options) nextState(name string, state, lowBits reg.GPVirtual, table string) {
+	DX := GP64()
+	if o.bmi2 {
+		tmp := GP64()
+		MOVQ(U32(16|(16<<8)), tmp)
+		BEXTRQ(tmp, state, DX)
+	} else {
+		MOVQ(state, DX)
+		SHRQ(U8(16), DX)
+		MOVWQZX(DX.As16(), DX)
+	}
+
+	ADDQ(lowBits, DX)
+
+	// Load table pointer
+	tablePtr := GP64()
+	Comment("Load ctx." + table)
+	ctx := Dereference(Param("ctx"))
+	tableA, err := ctx.Field(table).Base().Resolve()
+	if err != nil {
+		panic(err)
+	}
+	MOVQ(tableA.Addr, tablePtr)
+
+	// Check if below tablelog
+	assert(func(ok LabelRef) {
+		CMPQ(DX, U32(512))
+		JB(ok)
+	})
+	// Load new state
+	MOVQ(Mem{Base: tablePtr, Index: DX, Scale: 8}, state)
+}
+
 // getBits will return nbits bits from brValue.
 // If nbits == 0 it *may* jump to jmpZero, otherwise 0 is returned.
 func (o options) getBits(name string, nBits, brValue, brBitsRead reg.GPVirtual, jmpZero LabelRef) reg.GPVirtual {
@@ -647,6 +719,33 @@ func (o options) getBits(name string, nBits, brValue, brBitsRead reg.GPVirtual,
 	return BX
 }
 
+// getBits will return nbits bits from brValue.
+// If nbits == 0 then 0 is returned.
+func (o options) getBitsValue(name string, nBits, brValue, brBitsRead reg.GPVirtual) reg.GPVirtual {
+	BX := GP64()
+	CX := reg.CL
+	if o.bmi2 {
+		LEAQ(Mem{Base: brBitsRead, Index: nBits, Scale: 1}, CX.As64())
+		MOVQ(brValue, BX)
+		MOVQ(CX.As64(), brBitsRead)
+		ROLQ(CX, BX)
+		BZHIQ(nBits, BX, BX)
+	} else {
+		XORQ(BX, BX)
+		CMPQ(nBits, U8(0))
+		JZ(LabelRef(name + "_get_bits_value_zero"))
+		MOVQ(brBitsRead, CX.As64())
+		ADDQ(nBits, brBitsRead)
+		MOVQ(brValue, BX)
+		SHLQ(CX, BX)
+		MOVQ(nBits, CX.As64())
+		NEGQ(CX.As64())
+		SHRQ(CX, BX)
+		Label(name + "_get_bits_value_zero")
+	}
+	return BX
+}
+
 func (o options) adjustOffset(name string, moP, llP Mem, offsetB reg.GPVirtual, offsets *[3]reg.GPVirtual) (offset reg.GPVirtual) {
 	offset = GP64()
 	MOVQ(moP, offset)
diff --git a/zstd/seqdec.go b/zstd/seqdec.go
index e80139dd9c..b8295c74a4 100644
--- a/zstd/seqdec.go
+++ b/zstd/seqdec.go
@@ -188,6 +188,7 @@ func (s *sequenceDecs) execute(seqs []seqVals, hist []byte) error {
 			}
 		}
 	}
+
 	// Add final literals
 	copy(out[t:], s.literals)
 	if debugDecoder {
@@ -203,12 +204,11 @@ func (s *sequenceDecs) execute(seqs []seqVals, hist []byte) error {
 
 // decode sequences from the stream with the provided history.
 func (s *sequenceDecs) decodeSync(hist []byte) error {
-	if true {
-		supported, err := s.decodeSyncSimple(hist)
-		if supported {
-			return err
-		}
+	supported, err := s.decodeSyncSimple(hist)
+	if supported {
+		return err
 	}
+
 	br := s.br
 	seqs := s.nSeqs
 	startSize := len(s.out)
@@ -396,6 +396,7 @@ func (s *sequenceDecs) decodeSync(hist []byte) error {
 			ofState = ofTable[ofState.newState()&maxTableMask]
 		} else {
 			bits := br.get32BitsFast(nBits)
+
 			lowBits := uint16(bits >> ((ofState.nbBits() + mlState.nbBits()) & 31))
 			llState = llTable[(llState.newState()+lowBits)&maxTableMask]
 
diff --git a/zstd/seqdec_amd64.s b/zstd/seqdec_amd64.s
index 2585b2e988..fb1e6e16f5 100644
--- a/zstd/seqdec_amd64.s
+++ b/zstd/seqdec_amd64.s
@@ -705,60 +705,58 @@ sequenceDecs_decode_bmi2_fill_2_end:
 	MOVQ   CX, (R9)
 
 	// Fill bitreader for state updates
-	MOVQ   R13, (SP)
-	MOVQ   $0x00000808, CX
-	BEXTRQ CX, R8, R13
-	MOVQ   ctx+16(FP), CX
-	CMPQ   96(CX), $0x00
-	JZ     sequenceDecs_decode_bmi2_skip_update
-
-	// Update Literal Length State
-	MOVBQZX SI, R14
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, SI, SI
+	MOVQ    R13, (SP)
+	MOVQ    $0x00000808, CX
+	BEXTRQ  CX, R8, R13
+	MOVQ    ctx+16(FP), CX
+	CMPQ    96(CX), $0x00
+	JZ      sequenceDecs_decode_bmi2_skip_update
+	LEAQ    (SI)(DI*1), R14
+	ADDQ    R8, R14
+	MOVBQZX R14, R14
 	LEAQ    (DX)(R14*1), CX
 	MOVQ    AX, R15
 	MOVQ    CX, DX
 	ROLQ    CL, R15
 	BZHIQ   R14, R15, R15
-	ADDQ    R15, SI
 
-	// Load ctx.llTable
-	MOVQ ctx+16(FP), CX
-	MOVQ (CX), CX
-	MOVQ (CX)(SI*8), SI
+	// Update Offset State
+	MOVBQZX R8, CX
+	BZHIQ   CX, R15, R14
+	SHRXQ   CX, R15, R15
+	MOVQ    $0x00001010, CX
+	BEXTRQ  CX, R8, CX
+	ADDQ    R14, CX
+
+	// Load ctx.ofTable
+	MOVQ ctx+16(FP), R8
+	MOVQ 48(R8), R8
+	MOVQ (R8)(CX*8), R8
 
 	// Update Match Length State
-	MOVBQZX DI, R14
+	MOVBQZX DI, CX
+	BZHIQ   CX, R15, R14
+	SHRXQ   CX, R15, R15
 	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, DI, DI
-	LEAQ    (DX)(R14*1), CX
-	MOVQ    AX, R15
-	MOVQ    CX, DX
-	ROLQ    CL, R15
-	BZHIQ   R14, R15, R15
-	ADDQ    R15, DI
+	BEXTRQ  CX, DI, CX
+	ADDQ    R14, CX
 
 	// Load ctx.mlTable
-	MOVQ ctx+16(FP), CX
-	MOVQ 24(CX), CX
-	MOVQ (CX)(DI*8), DI
+	MOVQ ctx+16(FP), DI
+	MOVQ 24(DI), DI
+	MOVQ (DI)(CX*8), DI
 
-	// Update Offset State
-	MOVBQZX R8, R14
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, R8, R8
-	LEAQ    (DX)(R14*1), CX
-	MOVQ    AX, R15
-	MOVQ    CX, DX
-	ROLQ    CL, R15
-	BZHIQ   R14, R15, R15
-	ADDQ    R15, R8
+	// Update Literal Length State
+	MOVBQZX SI, CX
+	BZHIQ   CX, R15, CX
+	MOVQ    $0x00001010, R14
+	BEXTRQ  R14, SI, SI
+	ADDQ    CX, SI
 
-	// Load ctx.ofTable
+	// Load ctx.llTable
 	MOVQ ctx+16(FP), CX
-	MOVQ 48(CX), CX
-	MOVQ (CX)(R8*8), R8
+	MOVQ (CX), CX
+	MOVQ (CX)(SI*8), SI
 
 sequenceDecs_decode_bmi2_skip_update:
 	// Adjust offset
@@ -965,60 +963,58 @@ sequenceDecs_decode_56_bmi2_fill_end:
 	MOVQ   CX, (R9)
 
 	// Fill bitreader for state updates
-	MOVQ   R13, (SP)
-	MOVQ   $0x00000808, CX
-	BEXTRQ CX, R8, R13
-	MOVQ   ctx+16(FP), CX
-	CMPQ   96(CX), $0x00
-	JZ     sequenceDecs_decode_56_bmi2_skip_update
-
-	// Update Literal Length State
-	MOVBQZX SI, R14
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, SI, SI
+	MOVQ    R13, (SP)
+	MOVQ    $0x00000808, CX
+	BEXTRQ  CX, R8, R13
+	MOVQ    ctx+16(FP), CX
+	CMPQ    96(CX), $0x00
+	JZ      sequenceDecs_decode_56_bmi2_skip_update
+	LEAQ    (SI)(DI*1), R14
+	ADDQ    R8, R14
+	MOVBQZX R14, R14
 	LEAQ    (DX)(R14*1), CX
 	MOVQ    AX, R15
 	MOVQ    CX, DX
 	ROLQ    CL, R15
 	BZHIQ   R14, R15, R15
-	ADDQ    R15, SI
 
-	// Load ctx.llTable
-	MOVQ ctx+16(FP), CX
-	MOVQ (CX), CX
-	MOVQ (CX)(SI*8), SI
+	// Update Offset State
+	MOVBQZX R8, CX
+	BZHIQ   CX, R15, R14
+	SHRXQ   CX, R15, R15
+	MOVQ    $0x00001010, CX
+	BEXTRQ  CX, R8, CX
+	ADDQ    R14, CX
+
+	// Load ctx.ofTable
+	MOVQ ctx+16(FP), R8
+	MOVQ 48(R8), R8
+	MOVQ (R8)(CX*8), R8
 
 	// Update Match Length State
-	MOVBQZX DI, R14
+	MOVBQZX DI, CX
+	BZHIQ   CX, R15, R14
+	SHRXQ   CX, R15, R15
 	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, DI, DI
-	LEAQ    (DX)(R14*1), CX
-	MOVQ    AX, R15
-	MOVQ    CX, DX
-	ROLQ    CL, R15
-	BZHIQ   R14, R15, R15
-	ADDQ    R15, DI
+	BEXTRQ  CX, DI, CX
+	ADDQ    R14, CX
 
 	// Load ctx.mlTable
-	MOVQ ctx+16(FP), CX
-	MOVQ 24(CX), CX
-	MOVQ (CX)(DI*8), DI
+	MOVQ ctx+16(FP), DI
+	MOVQ 24(DI), DI
+	MOVQ (DI)(CX*8), DI
 
-	// Update Offset State
-	MOVBQZX R8, R14
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, R8, R8
-	LEAQ    (DX)(R14*1), CX
-	MOVQ    AX, R15
-	MOVQ    CX, DX
-	ROLQ    CL, R15
-	BZHIQ   R14, R15, R15
-	ADDQ    R15, R8
+	// Update Literal Length State
+	MOVBQZX SI, CX
+	BZHIQ   CX, R15, CX
+	MOVQ    $0x00001010, R14
+	BEXTRQ  R14, SI, SI
+	ADDQ    CX, SI
 
-	// Load ctx.ofTable
+	// Load ctx.llTable
 	MOVQ ctx+16(FP), CX
-	MOVQ 48(CX), CX
-	MOVQ (CX)(R8*8), R8
+	MOVQ (CX), CX
+	MOVQ (CX)(SI*8), SI
 
 sequenceDecs_decode_56_bmi2_skip_update:
 	// Adjust offset
@@ -2044,60 +2040,58 @@ sequenceDecs_decodeSync_bmi2_fill_2_end:
 	MOVQ   CX, 24(SP)
 
 	// Fill bitreader for state updates
-	MOVQ   R12, (SP)
-	MOVQ   $0x00000808, CX
-	BEXTRQ CX, R8, R12
-	MOVQ   ctx+16(FP), CX
-	CMPQ   96(CX), $0x00
-	JZ     sequenceDecs_decodeSync_bmi2_skip_update
-
-	// Update Literal Length State
-	MOVBQZX SI, R13
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, SI, SI
+	MOVQ    R12, (SP)
+	MOVQ    $0x00000808, CX
+	BEXTRQ  CX, R8, R12
+	MOVQ    ctx+16(FP), CX
+	CMPQ    96(CX), $0x00
+	JZ      sequenceDecs_decodeSync_bmi2_skip_update
+	LEAQ    (SI)(DI*1), R13
+	ADDQ    R8, R13
+	MOVBQZX R13, R13
 	LEAQ    (DX)(R13*1), CX
 	MOVQ    AX, R14
 	MOVQ    CX, DX
 	ROLQ    CL, R14
 	BZHIQ   R13, R14, R14
-	ADDQ    R14, SI
 
-	// Load ctx.llTable
-	MOVQ ctx+16(FP), CX
-	MOVQ (CX), CX
-	MOVQ (CX)(SI*8), SI
+	// Update Offset State
+	MOVBQZX R8, CX
+	BZHIQ   CX, R14, R13
+	SHRXQ   CX, R14, R14
+	MOVQ    $0x00001010, CX
+	BEXTRQ  CX, R8, CX
+	ADDQ    R13, CX
+
+	// Load ctx.ofTable
+	MOVQ ctx+16(FP), R8
+	MOVQ 48(R8), R8
+	MOVQ (R8)(CX*8), R8
 
 	// Update Match Length State
-	MOVBQZX DI, R13
+	MOVBQZX DI, CX
+	BZHIQ   CX, R14, R13
+	SHRXQ   CX, R14, R14
 	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, DI, DI
-	LEAQ    (DX)(R13*1), CX
-	MOVQ    AX, R14
-	MOVQ    CX, DX
-	ROLQ    CL, R14
-	BZHIQ   R13, R14, R14
-	ADDQ    R14, DI
+	BEXTRQ  CX, DI, CX
+	ADDQ    R13, CX
 
 	// Load ctx.mlTable
-	MOVQ ctx+16(FP), CX
-	MOVQ 24(CX), CX
-	MOVQ (CX)(DI*8), DI
+	MOVQ ctx+16(FP), DI
+	MOVQ 24(DI), DI
+	MOVQ (DI)(CX*8), DI
 
-	// Update Offset State
-	MOVBQZX R8, R13
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, R8, R8
-	LEAQ    (DX)(R13*1), CX
-	MOVQ    AX, R14
-	MOVQ    CX, DX
-	ROLQ    CL, R14
-	BZHIQ   R13, R14, R14
-	ADDQ    R14, R8
+	// Update Literal Length State
+	MOVBQZX SI, CX
+	BZHIQ   CX, R14, CX
+	MOVQ    $0x00001010, R13
+	BEXTRQ  R13, SI, SI
+	ADDQ    CX, SI
 
-	// Load ctx.ofTable
+	// Load ctx.llTable
 	MOVQ ctx+16(FP), CX
-	MOVQ 48(CX), CX
-	MOVQ (CX)(R8*8), R8
+	MOVQ (CX), CX
+	MOVQ (CX)(SI*8), SI
 
 sequenceDecs_decodeSync_bmi2_skip_update:
 	// Adjust offset
@@ -3108,60 +3102,58 @@ sequenceDecs_decodeSync_safe_bmi2_fill_2_end:
 	MOVQ   CX, 24(SP)
 
 	// Fill bitreader for state updates
-	MOVQ   R12, (SP)
-	MOVQ   $0x00000808, CX
-	BEXTRQ CX, R8, R12
-	MOVQ   ctx+16(FP), CX
-	CMPQ   96(CX), $0x00
-	JZ     sequenceDecs_decodeSync_safe_bmi2_skip_update
-
-	// Update Literal Length State
-	MOVBQZX SI, R13
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, SI, SI
+	MOVQ    R12, (SP)
+	MOVQ    $0x00000808, CX
+	BEXTRQ  CX, R8, R12
+	MOVQ    ctx+16(FP), CX
+	CMPQ    96(CX), $0x00
+	JZ      sequenceDecs_decodeSync_safe_bmi2_skip_update
+	LEAQ    (SI)(DI*1), R13
+	ADDQ    R8, R13
+	MOVBQZX R13, R13
 	LEAQ    (DX)(R13*1), CX
 	MOVQ    AX, R14
 	MOVQ    CX, DX
 	ROLQ    CL, R14
 	BZHIQ   R13, R14, R14
-	ADDQ    R14, SI
 
-	// Load ctx.llTable
-	MOVQ ctx+16(FP), CX
-	MOVQ (CX), CX
-	MOVQ (CX)(SI*8), SI
+	// Update Offset State
+	MOVBQZX R8, CX
+	BZHIQ   CX, R14, R13
+	SHRXQ   CX, R14, R14
+	MOVQ    $0x00001010, CX
+	BEXTRQ  CX, R8, CX
+	ADDQ    R13, CX
+
+	// Load ctx.ofTable
+	MOVQ ctx+16(FP), R8
+	MOVQ 48(R8), R8
+	MOVQ (R8)(CX*8), R8
 
 	// Update Match Length State
-	MOVBQZX DI, R13
+	MOVBQZX DI, CX
+	BZHIQ   CX, R14, R13
+	SHRXQ   CX, R14, R14
 	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, DI, DI
-	LEAQ    (DX)(R13*1), CX
-	MOVQ    AX, R14
-	MOVQ    CX, DX
-	ROLQ    CL, R14
-	BZHIQ   R13, R14, R14
-	ADDQ    R14, DI
+	BEXTRQ  CX, DI, CX
+	ADDQ    R13, CX
 
 	// Load ctx.mlTable
-	MOVQ ctx+16(FP), CX
-	MOVQ 24(CX), CX
-	MOVQ (CX)(DI*8), DI
+	MOVQ ctx+16(FP), DI
+	MOVQ 24(DI), DI
+	MOVQ (DI)(CX*8), DI
 
-	// Update Offset State
-	MOVBQZX R8, R13
-	MOVQ    $0x00001010, CX
-	BEXTRQ  CX, R8, R8
-	LEAQ    (DX)(R13*1), CX
-	MOVQ    AX, R14
-	MOVQ    CX, DX
-	ROLQ    CL, R14
-	BZHIQ   R13, R14, R14
-	ADDQ    R14, R8
+	// Update Literal Length State
+	MOVBQZX SI, CX
+	BZHIQ   CX, R14, CX
+	MOVQ    $0x00001010, R13
+	BEXTRQ  R13, SI, SI
+	ADDQ    CX, SI
 
-	// Load ctx.ofTable
+	// Load ctx.llTable
 	MOVQ ctx+16(FP), CX
-	MOVQ 48(CX), CX
-	MOVQ (CX)(R8*8), R8
+	MOVQ (CX), CX
+	MOVQ (CX)(SI*8), SI
 
 sequenceDecs_decodeSync_safe_bmi2_skip_update:
 	// Adjust offset