static_cast<X86Operand &>(*Operands[0]).setTokenValue(Repl);
}
+ // Moving a 32 or 16 bit value into a segment register has the same
+ // behavior. Modify such instructions to always take shorter form.
+ if ((Name == "mov" || Name == "movw" || Name == "movl") &&
+ (Operands.size() == 3)) {
+ X86Operand &Op1 = (X86Operand &)*Operands[1];
+ X86Operand &Op2 = (X86Operand &)*Operands[2];
+ SMLoc Loc = Op1.getEndLoc();
+ if (Op1.isReg() && Op2.isReg() &&
+ X86MCRegisterClasses[X86::SEGMENT_REGRegClassID].contains(
+ Op2.getReg()) &&
+ (X86MCRegisterClasses[X86::GR16RegClassID].contains(Op1.getReg()) ||
+ X86MCRegisterClasses[X86::GR32RegClassID].contains(Op1.getReg()))) {
+ // Change instruction name to match new instruction.
+ if (Name != "mov" && Name[3] == (is16BitMode() ? 'l' : 'w')) {
+ Name = is16BitMode() ? "movw" : "movl";
+ Operands[0] = X86Operand::CreateToken(Name, NameLoc);
+ }
+ // Select the correct equivalent 16-/32-bit source register.
+ unsigned Reg =
+ getX86SubSuperRegisterOrZero(Op1.getReg(), is16BitMode() ? 16 : 32);
+ Operands[1] = X86Operand::CreateReg(Reg, Loc, Loc);
+ }
+ }
+
// This is a terrible hack to handle "out[s]?[bwl]? %al, (%dx)" ->
// "outb %al, %dx". Out doesn't take a memory form, but this is a widely
// documented form in various unofficial manuals, so a lot of code uses it.
// CHECK: encoding: [0x67,0x8c,0x08]
movw %cs, (%eax)
-// CHECK: movl %eax, %cs
-// CHECK: encoding: [0x66,0x8e,0xc8]
+// CHECK: movw %ax, %cs
+// CHECK: encoding: [0x8e,0xc8]
movl %eax, %cs
+// CHECK: movw %ax, %cs
+// CHECK: encoding: [0x8e,0xc8]
+ mov %eax, %cs
+
+// CHECK: movw %ax, %cs
+// CHECK: encoding: [0x8e,0xc8]
+ movw %ax, %cs
+
+// CHECK: movw %ax, %cs
+// CHECK: encoding: [0x8e,0xc8]
+ mov %ax, %cs
+
// CHECK: movl (%eax), %cs
// CHECK: encoding: [0x67,0x66,0x8e,0x08]
movl (%eax), %cs
// CHECK: encoding: [0x8e,0xc8]
movl %eax, %cs
+// CHECK: movl %eax, %cs
+// CHECK: encoding: [0x8e,0xc8]
+ movw %ax, %cs
+
+// CHECK: movl %eax, %cs
+// CHECK: encoding: [0x8e,0xc8]
+ mov %eax, %cs
+
+// CHECK: movl %eax, %cs
+// CHECK: encoding: [0x8e,0xc8]
+ mov %ax, %cs
+
// CHECK: movl (%eax), %cs
// CHECK: encoding: [0x8e,0x08]
movl (%eax), %cs