[hjl@gnu-6 sse5-1]$ cat x.s .text _start: pmacssww %xmm1, 0x100000(%ebx), %xmm2, %xmm1 .intel_syntax noprefix [hjl@gnu-6 sse5-1]$ make x.o ./as --32 -o x.o x.s [hjl@gnu-6 sse5-1]$ ./objdump -dw x.o x.o: file format elf32-i386 Disassembly of section .text: 00000000 <_start>: 0: 0f 24 85 93 10 00 00 10 00 pmacssww %xmm1,%xmm2,0x100000(%ebx),%xmm1 [hjl@gnu-6 sse5-1]$
SSE5 was removed.