/*
** A20 gate enable: AX = 2401h
** CF clear if successful
** AH = 00h
** CF set on error
** AH = status
** 01h keyboard controller is in secure mode
** 86h function not supported
*/
static int emulate_int15_a20_enable()
{
info->vm.cpu.gpr->rax.bhigh = 0;
__rflags.cf = 0;
__post_access(__rflags);
dev_a20_set(1);
return VM_DONE;
}
/*
** A20 gate disable: AX = 2400h
** CF clear if successful
** AH = 00h
** CF set on error
** AH = status
** 01h keyboard controller is in secure mode
** 86h function not supported
*/
static int emulate_int15_a20_disable()
{
info->vm.cpu.gpr->rax.bhigh = 0;
__rflags.cf = 0;
__post_access(__rflags);
dev_a20_set(0);
return EMU_SUCCESS;
}
int __dev_kbd_data(kbd_t *kbd, io_insn_t *io)
{
raw64_t *rax = &info->vm.cpu.gpr->rax;
if(io->in)
{
rax->blow = in(io->port);
/* Return the value the VM expects to see for the a20 bit */
if(kbd->last_cmd == KBD_CMD_READ_O_PORT)
{
rax->blow &= ~KBD_OUTPUT_PORT_A20;
rax->blow |= (kbd->output_port.a20 ? KBD_OUTPUT_PORT_A20 : 0);
}
}
else
{
if(kbd->last_cmd == KBD_CMD_WRITE_O_PORT)
{
kbd->output_port.raw = rax->blow;
/* if(kbd->output_port.sys_rst) */
/* panic("keyboard controller system reset"); */
dev_a20_set(kbd->output_port.a20);
/* Don't let the VM _actually_ disable the a20 line */
if(!kbd->output_port.a20)
rax->blow |= KBD_OUTPUT_PORT_A20;
}
out(rax->blow, io->port);
}
return VM_DONE;
}
