Opcodes $60FF, $61FF, $F518

[dirkwhoffmann]

More findings:

• Opcode $60FF:

  In 68000 mode, opcode $60FF disassembles to ILLEGAL, because this bit bittern marks the BRA 32-bit-displacement instruction on the 68020+. On the 68000/68010, it should execute a BRA with a byte-displacement of $FF, I think.

The emulation code does the right thing. Hence, only the disassembler output is wrong.

static void m68k_op_bra_32(void)
{
	if(CPU_TYPE_IS_EC020_PLUS(CPU_TYPE))
	{
	...
	}
	else
	{
		m68ki_trace_t0();				   /* auto-disable (see m68kcpu.h) */
		m68ki_branch_8(MASK_OUT_ABOVE_8(REG_IR));
		if(REG_PC == REG_PPC)
			USE_ALL_CYCLES();
	}
}

• Opcode $61FF: Same as $60FF, just for BSR.

• Opcode $f518: (PFLUSH on 68040+)

static void m68k_op_pflush_32(void)
{
	if(CPU_TYPE_IS_040_PLUS(CPU_TYPE))
	{
		// Nothing to do, unless address translation cache is emulated
		return;
	}
         m68ki_exception_illegal();
}

On models 68030-, this opcode should trigger a line F exception (m68ki_exception_1111), not an illegal exception (m68ki_exception_illegal).