primoemu.c

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/* Xep128: Minimalistic Enterprise-128 emulator with focus on "exotic" hardware
   Copyright (C)2016 LGB (Gábor Lénárt) <lgblgblgb@gmail.com>
   http://xep128.lgb.hu/
 
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 
#include "xep128.h"
#include "primoemu.h"
#include "xemu/z80.h"
#include "cpu.h"
#include "dave.h"
#include "nick.h"
#include "zxemu.h"
 
#include "main.h"
 
 
 
int primo_on = 0;
int primo_nmi_enabled = 0;
int primo_rom_seg = -1;
 
 
// translates EP keyboard matrix  positions into Primo scan keys, indexed by primo scan keys
const Uint8 primo_key_trans[] = {
        0x22,           // scan 0 Y
        0x73,           // scan 1 UP-ARROW
        0x15,           // scan 2 S
        0x07,           // scan 3 SHIFT
        0x25,           // scan 4 E
        0xFF,           // scan 5 UPPER
        0x26,           // scan 6 W
        0x17,           // scan 7 CTR
        0x13,           // scan 8 D
        0x35,           // scan 9 3 #
        0x05,           // scan 10 X
        0x36,           // scan 11 2 "
        0x21,           // scan 12 Q
        0x31,           // scan 13 1 !
        0x16,           // scan 14 A
        0x71,           // scan 15 DOWN-ARROW
        0x03,           // scan 16 C
        0xFF,           // scan 17 ----
        0x14,           // scan 18 F
        0xFF,           // scan 19 ----
        0x23,           // scan 20 R
        0xFF,           // scan 21 ----
        0x24,           // scan 22 T
        0x30,           // scan 23 7 /
        0x10,           // scan 24 H
        0x86,           // scan 25 SPACE
        0x02,           // scan 26 B
        0x32,           // scan 27 6 &
        0x12,           // scan 28 G
        0x34,           // scan 29 5 %
        0x04,           // scan 30 V
        0x33,           // scan 31 4 $
        0x00,           // scan 32 N
        0x50,           // scan 33 8 (
        0x06,           // scan 34 Z
        0xFF,           // scan 35 + ?
        0x20,           // scan 36 U
        0x54,           // scan 37 0
        0x60,           // scan 38 J
        0xFF,           // scan 39 > <
        0x64,           // scan 40 L
        0x53,           // scan 41 - i
        0x62,           // scan 42 K
        0x84,           // scan 43 . :
        0x80,           // scan 44 M
        0x52,           // scan 45 9 ;
        0x90,           // scan 46 I
        0x82,           // scan 47 ,
        0xFF,           // scan 48 U"
        0x65,           // scan 49 ' #
        0x94,           // scan 50 P
        0xFF,           // scan 51 u' u"
        0x92,           // scan 52 O
        0xFF,           // scan 53 CLS
        0xFF,           // scan 54 ----
        0x76,           // scan 55 RETURN
        0xFF,           // scan 56 ----
        0x75,           // scan 57 LEFT-ARROW
        0xFF,           // scan 58 E'
        0xFF,           // scan 59 o'
        0xFF,           // scan 60 A'
        0x72,           // scan 61 RIGHT-ARROW
        0xFF,           // scan 62 O:
        0x37            // scan 63 BRK
};
 
 
#define EP_KBDM_SCAN(sc,resval) ((kbd_matrix[(sc) >> 4] & (1 << ((sc) & 15))) ? 0 : (resval))
 
// F1
#define PRIMOEMU_HOTKEY_RESET 0x47
 
 
void primo_switch ( Uint8 data )
{
        if (data & 128) {
                if (data & 64)
                        primo_write_io(0, 0);
                if (primo_on)
                        return;
                primo_on = 0x40;        // the value is important, used by port "limit" for lower primo area!
                zxemu_switch(0);        // switch ZX Spectrum emulation off, if already enabled for some reason ...
        } else {
                if (!primo_on)
                        return;
                primo_on = 0;
        }
        DEBUG("PRIMOEMU: emulation is turned %s." NL, primo_on ? "ON" : "OFF");
        nmi_pending = 0;
}
 
 
static int primo_scan_key ( int scan )
{
        scan = primo_key_trans[scan];
        if (scan == 0xFF) return 0;
        return EP_KBDM_SCAN(scan, 1);
}
 
 
Uint8 primo_read_io ( Uint8 port )
{
        // Primo does the very same for all I/O ports in the range of 0-3F!
        // EXCEPT bit 0 which is the state of the key given by the port number.
        return (vsync ? 32 : 0) | EP_KBDM_SCAN(PRIMOEMU_HOTKEY_RESET, 2) | primo_scan_key(port);
}
 
 
#define LD1HI_PV1 (((PRIMO_VID_SEG << 6) + 0x28) & 0xFF)
#define LD1HI_PV0 (((PRIMO_VID_SEG << 6) + 0x08) & 0xFF)
 
 
void primo_write_io ( Uint8 port, Uint8 data )
{
        // Primo does the  very same for all I/O ports in the range of 0-3F!
        primo_nmi_enabled = data & 128;                         // bit 7: NMI enabled, this variable is "cloned" as nmi_pending by VINT in dave.c
        ports[0xA8] = ports[0xAC] = (data & 16) ? 63 : 0;       // bit 4, speaker control, pass to Dave in D/A mode
        memory[(PRIMO_LPT_SEG << 14) + 5] = (data & 8) ? LD1HI_PV1 : LD1HI_PV0;         // bit 3: display page: set LPB LD1 high (LPB should be at segment 0xFD, and 0xFC is for primo 0xC000-0xFFFF)
}
 
 
int primo_search_rom ( void )
{
        int a;
        for (a = 0; a < 0xFC; a++)
                if (memory_segment_map[a] == ROM_SEGMENT && !memcmp(memory + (a << 14) + 0x168, "PRIMO", 5)) {
                        DEBUG("PRIMO: found Primo ROM in segment %02Xh, good" NL, a);
                        return a;
                }
        DEBUG("PRIMO: not found Primo ROM in the loaded ROMs ..." NL);
        return -1;
}
 
 
static const Uint8 primo_lpt[] = {
        // the USEFULL area of the screen, this must be the FIRST LPB in our LPT.
        // LPIXEL 2 colour mode is used, 192 scanlines are used
        256-192,14|16,  15, 47,  0,0,0,0,     1,0xFF,0,0,0,0,0,0,
        // bottom not used area ... 47 scanlines
        256-47,  2 | 128,  6, 63,  0,0,0,0,     0,0,0,0,0,0,0,0,        // 128 = ask for VINT, which is cloned as NMI in primo mode
        // SYNC etc stuffs ...
        256-3 ,  0, 63,  0,  0,0,0,0,     0,0,0,0,0,0,0,0,
        256-2 ,  0,  6, 63,  0,0,0,0,     0,0,0,0,0,0,0,0,
        256-1 ,  0, 63, 32,  0,0,0,0,     0,0,0,0,0,0,0,0,
        256-19,  2,  6, 63,  0,0,0,0,     0,0,0,0,0,0,0,0,
        // upper not used area ... 48 scanlines, the RELOAD bit must be set!!!!
        256-48,  3,  6, 63,  0,0,0,0,     0,0,0,0,0,0,0,0
};
#define MEMORY_BACKUP_SIZE (0xC000 + sizeof primo_lpt)
static Uint8 memory_backup[MEMORY_BACKUP_SIZE];
static Uint8 ports_backup[0x100];
static Z80EX_CONTEXT z80ex_backup;
 
 
 
void primo_emulator_exit ( void )
{
        int a;
        ports_backup[0x83] |= 128 | 64;
        for (a = 0x80; a < 0x84; a++)
                z80ex_pwrite_cb(a, ports_backup[a]);    // restore Nick registers
        for (a = 0xA0; a < 0xB5; a++)
                z80ex_pwrite_cb(a, ports_backup[a]);    // restore Dave registers
        memcpy(memory + 0xFA * 0x4000, memory_backup, MEMORY_BACKUP_SIZE); // restore memory
        primo_switch(0);        // turn Primo mode OFF
        //z80ex.int = 1;                // enable interrupts (?)
        //memcpy(&z80ex, &z80ex_backup, sizeof(Z80EX_CONTEXT));
        //z80ex.prefix = 0;     // turn prefix off, because last opc was the ED trap for XEP ROM!
        //Z80_PC--; // nah ...
        //xep_accept_trap = 0;
        set_cpu_clock(DEFAULT_CPU_CLOCK);
}
 
 
void primo_emulator_execute ( void )
{
        int a;
        /* Save state of various things to be able to revert into EP mode later, without any data lost */
        memcpy(memory_backup, memory + 0xFA * 0x4000, MEMORY_BACKUP_SIZE);      // save memory
        memcpy(ports_backup, ports, 0x100);     // backup ports [note: on restore, we don't want to rewrite all values, maybe only Dave/Nick!
        memcpy(&z80ex_backup, &z80ex, sizeof(Z80EX_CONTEXT));
 
//      memcpy();       // save Dave registers
//      memcpy();       // save Nick registers
 
        /* set an LPT */
        memcpy(memory + (PRIMO_LPT_SEG << 14), primo_lpt, sizeof primo_lpt);
        z80ex_pwrite_cb(0x82, (PRIMO_LPT_SEG << 10) & 0xFF);    // LPT address, low byte
        z80ex_pwrite_cb(0x83, ((PRIMO_LPT_SEG << 2) & 0xF));
        z80ex_pwrite_cb(0x83, ((PRIMO_LPT_SEG << 2) & 0xF) | 64);
        z80ex_pwrite_cb(0x83, ((PRIMO_LPT_SEG << 2) & 0xF) | 64 | 128);
        z80ex_pwrite_cb(0x81, 0);       // border color
        /* do our stuffs ... */
        z80ex_pwrite_cb(0xA7, 8 | 16);  // D/A mode for Dave audio
        for (a = 0xA8; a < 0xB0; a++)
                z80ex_pwrite_cb(a, 0);  // volumes of L/H channels
        z80ex_pwrite_cb(0xB4, 0xAA);    // disable all interrupts on Dave (z80 won't get INT but the cloned NMI directly from Nick "translated" from VINT) and reset latches
        z80ex_pwrite_cb(0xB0, PRIMO_ROM_SEG);   // first segment is the Primo ROM now
        z80ex_pwrite_cb(0xB1, PRIMO_MEM1_SEG);  // normal RAM segment
        z80ex_pwrite_cb(0xB2, PRIMO_MEM2_SEG);  // normal RAM segment
        z80ex_pwrite_cb(0xB3, PRIMO_VID_SEG);   // a video segment as the Primo video RAM
        primo_switch(128 | 64);         // turn on Primo I/O mode
        Z80_PC = 0;                     // Z80 reset address to the Primo ROM
        z80ex_reset();                  // reset the CPU only!!
        set_ep_cpu(CPU_Z80);            // good old Z80 NMOS CPU is selected
        set_cpu_clock(2500000);
}