WC> (defun foo ()
      (cmpeq-i8-mask (%make-simd-pack-ub32 #x00000100 #x00000200 #x2A000000 #x00000000)
                     (set-i8 42)))
FOO
WC> (disassemble #'foo)
; disassembly for FOO
; Size: 127 bytes. Origin: #x53855FBC                         ; FOO
; 5FBC:       498B4510         MOV RAX, [R13+16]              ; thread.binding-stack-pointer
; 5FC0:       488945F8         MOV [RBP-8], RAX
; 5FC4:       41807D3800       CMP BYTE PTR [R13+56], 0       ; thread.stepping
; 5FC9:       7402             JEQ L0
; 5FCB:       CC0E             INT3 14                        ; single-step trap (before)
; 5FCD: L0:   B82A000000       MOV EAX, 42
; 5FD2:       660FEFC0         PXOR XMM0, XMM0
; 5FD6:       660F6EC8         MOVD XMM1, EAX
; 5FDA:       660F3800C8       PSHUFB XMM1, XMM0
; 5FDF:       41807D3800       CMP BYTE PTR [R13+56], 0       ; thread.stepping
; 5FE4:       7402             JEQ L1
; 5FE6:       CC0E             INT3 14                        ; single-step trap (before)
; 5FE8: L1:   660F6F05A0FFFFFF MOVDQA XMM0, [RIP-96]          ; [#x53855F90]
; 5FF0:       660F74C1         PCMPEQB XMM0, XMM1
; 5FF4:       49896D28         MOV [R13+40], RBP              ; thread.pseudo-atomic-bits
; 5FF8:       498B5568         MOV RDX, [R13+104]             ; thread.alloc-region
; 5FFC:       4C8D5A20         LEA R11, [RDX+32]
; 6000:       4D3B5D70         CMP R11, [R13+112]
; 6004:       7729             JNBE L4
; 6006:       4D895D68         MOV [R13+104], R11             ; thread.alloc-region
; 600A: L2:   66C7026503       MOV WORD PTR [RDX], 869
; 600F:       80CA0F           OR DL, 15
; 6012:       49316D28         XOR [R13+40], RBP              ; thread.pseudo-atomic-bits
; 6016:       7402             JEQ L3
; 6018:       CC09             INT3 9                         ; pending interrupt trap
; 601A: L3:   48C742F900000000 MOV QWORD PTR [RDX-7], #x0     ; current_thread
; 6022:       660F7F4201       MOVDQA [RDX+1], XMM0
; 6027:       488BE5           MOV RSP, RBP
; 602A:       F8               CLC
; 602B:       5D               POP RBP
; 602C:       C3               RET
; 602D:       CC10             INT3 16                        ; Invalid argument count trap
; 602F: L4:   6A20             PUSH 32
; 6031:       FF142528001052   CALL QWORD PTR [#x52100028]    ; ALLOC-TRAMP
; 6038:       5A               POP RDX
; 6039:       EBCF             JMP L2
NIL