.code16gcc, i386, and loop/jcc/jmp data-size overrides

[No Name]

Would it be ok for gas to generate extra size prefixes when compiling with 
code16gcc?

Like that the produced object with 16bit code could run with an EIP > 
0xffff.
It would seem that the spirit of code16gcc is to be 32bit allover anyway.

The attached patch is probably incomplete, "jcxz" should be tweaked also. 
And maybe the "loop/jcxz" handling is trickier due to suffixes manipulating 
addr-sizes instead of the data-sizes.

* code
.L19:
	movl	-8(%ebp), %eax
	addl	8(%ebp), %eax
	cmpb	$0, (%eax)
	jne	.L21
!!>>	jmp	.L20 <<!!
.L21:

* original gnu assembler
After reloc to 0x40000, executing the jmp cause eip to be truncated to 16bit 
(data size).

	67 66 8b 45 f8       	addr32 mov 0xfffffff8(%ebp),%eax
	67 66 03 45 08       	addr32 add 0x8(%ebp),%eax
	67 80 38 00          	addr32 cmpb $0x0,(%eax)
	75 03                	jne    40250 <printf+0x2f>
!!>>	e9 68 01             	jmp    3b8 <SEL_GDT_USER3+0x328> <<!!
	67 66 8b 45 f8       	addr32 mov 0xfffffff8(%ebp),%eax
	67 66 03 45 08       	addr32 add 0x8(%ebp),%eax

* with the attached binutils 1.16 patch

	67 66 8b 45 f8       	addr32 mov 0xfffffff8(%ebp),%eax
	67 66 03 45 08       	addr32 add 0x8(%ebp),%eax
	67 80 38 00          	addr32 cmpb $0x0,(%eax)
	66                   	data32
	75 06                	jne    40262 <printf+0x33>
!!>>	66 e9 8a 01 00 00    	jmpl   403ec <printf+0x1bd> <<!!
	67 66 8b 45 f8       	addr32 mov 0xfffffff8(%ebp),%eax
	67 66 03 45 08       	addr32 add 0x8(%ebp),%eax

--
jpa

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