For EVEX instructions, /is4 can contain a fifth register bit, encoded
in bit 3 of the imm8. Properly generate this case, and simplifiy the
/is4 generation code somewhat.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cherry picked and ported from nasm-2.12.xx commit
976ba730622ae7c2d5e88d4fb4477ff96c1cd3f4.
Resolved Conflicts:
asm/assemble.c