Index: src/runtime/lookup-asm/lookup-asm-x86-elf.S
==================================================================
--- src/runtime/lookup-asm/lookup-asm-x86-elf.S
+++ src/runtime/lookup-asm/lookup-asm-x86-elf.S
@@ -61,19 +61,18 @@
 	add	eax, offset _GLOBAL_OFFSET_TABLE_
 	lea	eax, [eax+\not_found@GOTOFF]
 	jmp	eax
 
 .Ltagged_pointer_\name:
-	and	dl, 0xF
-	shr	dl, 1
+	and	dl, 0xE
 	movzx	edx, dl
 
 	call	get_eip
 	add	eax, offset _GLOBAL_OFFSET_TABLE_
 
 	lea	eax, [eax+objc_tagged_pointer_classes@GOTOFF]
-	mov	edx, [eax+edx*4]
+	mov	edx, [eax+edx*2]
 	mov	edx, [edx+32]
 
 	jmp	short .Lmain_\name
 .type \name, %function
 .size \name, .-\name

Index: src/runtime/lookup-asm/lookup-asm-x86-win32.S
==================================================================
--- src/runtime/lookup-asm/lookup-asm-x86-win32.S
+++ src/runtime/lookup-asm/lookup-asm-x86-win32.S
@@ -53,16 +53,15 @@
 	jz	\not_found
 
 	ret
 
 .Ltagged_pointer_\name:
-	and	dl, 0xF
-	shr	dl, 1
+	and	dl, 0xE
 	movzx	edx, dl
 
 	mov	eax, offset _objc_tagged_pointer_classes
-	mov	edx, [eax+edx*4]
+	mov	edx, [eax+edx*2]
 	mov	edx, [edx+32]
 
 	jmp	short .Lmain_\name
 .endm
 

Index: src/runtime/lookup-asm/lookup-asm-x86_64-elf.S
==================================================================
--- src/runtime/lookup-asm/lookup-asm-x86_64-elf.S
+++ src/runtime/lookup-asm/lookup-asm-x86_64-elf.S
@@ -54,16 +54,15 @@
 	jz	short \not_found@PLT
 
 	ret
 
 .Ltagged_pointer_\name:
-	and	dil, 0xF
-	shr	dil, 1
+	and	dil, 0xE
 	movzx	r8, dil
 
 	mov	rax, [rip+objc_tagged_pointer_classes@GOTPCREL]
-	mov	r8, [rax+r8*8]
+	mov	r8, [rax+r8*4]
 	mov	r8, [r8+64]
 
 	jmp	short .Lmain_\name
 .type \name, %function
 .size \name, .-\name

Index: src/runtime/lookup-asm/lookup-asm-x86_64-macho.S
==================================================================
--- src/runtime/lookup-asm/lookup-asm-x86_64-macho.S
+++ src/runtime/lookup-asm/lookup-asm-x86_64-macho.S
@@ -52,16 +52,15 @@
 	jz	$1
 
 	ret
 
 Ltagged_pointer_$0:
-	and	dil, 0xF
-	shr	dil, 1
+	and	dil, 0xE
 	movzx	r8, dil
 
 	mov	rax, [rip+_objc_tagged_pointer_classes]
-	mov	r8, [rax+r8*8]
+	mov	r8, [rax+r8*4]
 	mov	r8, [r8+64]
 
 	jmp	Lmain_$0
 .endmacro
 

Index: src/runtime/lookup-asm/lookup-asm-x86_64-win64.S
==================================================================
--- src/runtime/lookup-asm/lookup-asm-x86_64-win64.S
+++ src/runtime/lookup-asm/lookup-asm-x86_64-win64.S
@@ -60,16 +60,15 @@
 	mov	rcx, r10
 	mov	rdx, r11
 	jmp	\not_found
 
 .Ltagged_pointer_\name:
-	and	cl, 0xF
-	shr	cl, 1
+	and	cl, 0xE
 	movzx	r8, cl
 
 	mov	rax, offset objc_tagged_pointer_classes
-	mov	r8, [rax+r8*8]
+	mov	r8, [rax+r8*4]
 	mov	r8, [r8+56]
 
 	jmp	short .Lmain_\name
 .endm