From 3e4a511bee874d73f9f749cc8cf3bc748b4d47b5 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 22 Dec 2023 09:34:10 +0100 Subject: x86-64: refuse "high" 8-bit regs with .insn and VEX/XOP/EVEX encodings Much like REX, those encodings - if permitting 8-bit regs at all, i.e. only starting with APX - permit use of "new" 8-bit registers only. %ah, %ch, %dh, and %bh cannot be encoded and hence should be rejected. Permit their use outside of 64-bit code though, as "new" registers simply don't exist there. --- gas/config/tc-i386.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'gas') diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c index 6e2f6e5..cdd3b55 100644 --- a/gas/config/tc-i386.c +++ b/gas/config/tc-i386.c @@ -11485,6 +11485,16 @@ s_insn (int dummy ATTRIBUTE_UNUSED) for (j = i.imm_operands; j < i.operands; ++j) { + /* Look for 8-bit operands that use old registers. */ + if (i.vec_encoding != vex_encoding_default + && flag_code == CODE_64BIT + && i.types[j].bitfield.class == Reg + && i.types[j].bitfield.byte + && !(i.op[j].regs->reg_flags & RegRex64) + && i.op[j].regs->reg_num > 3) + as_bad (_("can't encode register '%s%s' with VEX/XOP/EVEX"), + register_prefix, i.op[j].regs->reg_name); + i.types[j].bitfield.instance = InstanceNone; if (operand_type_check (i.types[j], disp)) -- cgit v1.1