/**
* mdp_host_reg_set_all_z80(): Set all Z80 registers.
* @param reg_struct Pointer to mdp_reg_psg_t struct to get the registers from.
* @return MDP error code.
*/
static int mdp_host_reg_set_all_z80(void *reg_struct)
{
mdp_reg_z80_t *reg_z80 = (mdp_reg_z80_t*)reg_struct;
/* Main registers. */
mdZ80_set_AF(&M_Z80, reg_z80->AF);
M_Z80.BC.w.BC = reg_z80->BC;
M_Z80.DE.w.DE = reg_z80->DE;
M_Z80.HL.w.HL = reg_z80->HL;
M_Z80.IX.w.IX = reg_z80->IX;
M_Z80.IY.w.IY = reg_z80->IY;
/* Shadow registers. */
mdZ80_set_AF2(&M_Z80, reg_z80->AF2);
M_Z80.BC2.w.BC2 = reg_z80->BC2;
M_Z80.DE2.w.DE2 = reg_z80->DE2;
M_Z80.HL2.w.HL2 = reg_z80->HL2;
/* Other registers. */
mdZ80_set_PC(&M_Z80, reg_z80->PC);
M_Z80.I = reg_z80->I;
M_Z80.R.b.R1 = reg_z80->R;
M_Z80.IM = reg_z80->IM & 3;
M_Z80.IFF.b.IFF1 = (reg_z80->IFF & 1);
M_Z80.IFF.b.IFF2 = ((reg_z80->IFF & 2) >> 1);
return MDP_ERR_OK;
}
/**
* Reset the Z80 CPU.
* This is equivalent to asserting the !RESET line.
* @param z80 Pointer to Z80 context.
*/
void mdZ80_soft_reset(mdZ80_context *z80)
{
/**
* References:
* [1] "The Undocumented Z80 Docuemnted" by Sean Young, v0.91 (2005/09/18)
* [2] http://gs_server.gerbilsoft.ddns.info/bugs/show_bug.cgi?id=47
*/
// NOTE: Both [1] and [2] say that other registers are *not* touched
// when !RESET is asserted, so they're left as-is.
// TODO: Write a test program for MD, then test it on actual hardware.
// Z80 program starts at 0x0000.
mdZ80_set_PC(z80, 0); // old Gens; [1]
// TODO: Are IX and IY actually reset on !RESET?
z80->IX.w = 0xFFFF; // old Gens; also genplus-gx
z80->IY.w = 0xFFFF; // old Gens; also genplus-gx
// TODO: Initialize AF2 to 0xFFFF?
mdZ80_set_AF(z80, 0xFFFF); // [1]; Gens originally used 0x4000 (ZF only).
z80->SP.w = 0xFFFF; // [1]
z80->IFF = 0; // [1]
z80->R = 0; // [2]
z80->I = 0; // [2]
z80->IM = 0; // [1]
}
