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emul/z80: decouple SDC and SPI

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My idea of plugging a RC2014 bridge directly onto a Sega Master System
cartridge doesn't work. The SMS eats all I/O addr space, we can't use
it. Therefore, this naive idea, in the emulator, of reusing sdc.c in
sms.c as-is, doesn't work either.

I'll have to find another way of communicating to a SPI device on the
SMS. I'll probably do it through a controller port. Meanwhile, I need
to decouple SPI from SDC in the emulator code so that I can reuse
sdc.c. This is what is done here.
This commit is contained in:
Virgil Dupras 2020-10-29 15:01:25 -04:00
parent e31527f5ac
commit 97a46a7b9b
9 changed files with 95 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
emul/z80/Makefile
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@ -1,6 +1,6 @@
TARGETS = forth rc2014 sms ti84
OBJS = emul.o z80.o
RC2014_OBJS = $(OBJS) sio.o acia.o sdc.o
RC2014_OBJS = $(OBJS) sio.o acia.o sdc.o rc2014_spi.o
SMS_OBJS = $(OBJS) sms_vdp.o sms_ports.o sms_pad.o ps2_kbd.o sdc.o
TI84_OBJS = $(OBJS) t6a04.o ti84_kbd.o
CDIR = ../../cvm

1
emul/z80/emul.h
View File

@ -5,6 +5,7 @@
typedef byte (*IORD) ();
typedef void (*IOWR) (byte data);
typedef byte (*EXCH) (byte data);
typedef struct {
Z80Context cpu;

27
emul/z80/rc2014.c
View File

@ -15,6 +15,7 @@
#include "acia.h"
#include "sio.h"
#include "sdc.h"
#include "rc2014_spi.h"
#define RAMSTART 0x8000
#define ACIA_CTL_PORT 0x80
@ -29,6 +30,7 @@ bool use_sio = false;
static ACIA acia;
static SIO sio;
static SDC sdc;
static SPI spi;
static uint8_t iord_acia_ctl()
{
@ -70,26 +72,28 @@ static void iowr_sio_data(uint8_t val)
sio_adata_wr(&sio, val);
}
static uint8_t iord_sdc_spi()
static uint8_t iord_spi()
{
return sdc_spi_rd(&sdc);
return spi_rd(&spi);
}
static void iowr_sdc_spi(uint8_t val)
static void iowr_spi(uint8_t val)
{
sdc_spi_wr(&sdc, val);
spi_wr(&spi, val);
}
byte spix_sdc(byte val) { return sdc_spix(&sdc, val); }
// in emulation, exchanges are always instantaneous, so we
// always report as ready.
static uint8_t iord_sdc_ctl()
static uint8_t iord_spi_ctl()
{
return 0;
}
static void iowr_sdc_ctl(uint8_t val)
static void iowr_spi_ctl(uint8_t val)
{
sdc_ctl_wr(&sdc, val);
spi_ctl_wr(&spi, val);
}
static bool has_irq()
@ -134,6 +138,7 @@ int main(int argc, char *argv[])
acia_init(&acia);
sio_init(&sio);
sdc_init(&sdc);
spi_init(&spi, spix_sdc);
while ((ch = getopt(argc, argv, "sc:")) != -1) {
switch (ch) {
@ -198,10 +203,10 @@ int main(int argc, char *argv[])
m->iowr[ACIA_CTL_PORT] = iowr_acia_ctl;
m->iowr[ACIA_DATA_PORT] = iowr_acia_data;
}
m->iord[SDC_SPI] = iord_sdc_spi;
m->iowr[SDC_SPI] = iowr_sdc_spi;
m->iord[SDC_CTL] = iord_sdc_ctl;
m->iowr[SDC_CTL] = iowr_sdc_ctl;
m->iord[SDC_SPI] = iord_spi;
m->iowr[SDC_SPI] = iowr_spi;
m->iord[SDC_CTL] = iord_spi_ctl;
m->iowr[SDC_CTL] = iowr_spi_ctl;
char tosend = 0;
while (emul_step()) {

28
emul/z80/rc2014_spi.c Normal file
View File

@ -0,0 +1,28 @@
#include "rc2014_spi.h"
void spi_init(SPI *spi, EXCH spixfn)
{
spi->selected = false;
spi->resp = 0xff;
spi->spixfn = spixfn;
}
// TODO: for now, any nonzero value enables the SPI. To allow
// emulation of systems with multi-devices SPI relay, change
// this.
void spi_ctl_wr(SPI *spi, byte val)
{
spi->selected = val;
}
void spi_wr(SPI *spi, byte val)
{
if (spi->selected) {
spi->resp = spi->spixfn(val);
}
}
byte spi_rd(SPI *spi)
{
return spi->selected ? spi->resp : 0xff;
}

17
emul/z80/rc2014_spi.h Normal file
View File

@ -0,0 +1,17 @@
#include "emul.h"
/* Emulates a SPI relay designed for the RC2014, enabled by poking on the CTL
port, then allowing a SPI exchange by writing to, then reading from, the
data port.
*/
typedef struct {
bool selected;
byte resp;
EXCH spixfn;
} SPI;
void spi_init(SPI *spi, EXCH spixfn);
void spi_ctl_wr(SPI *spi, byte val);
void spi_wr(SPI *spi, byte val);
byte spi_rd(SPI *spi);

60
emul/z80/sdc.c
View File

@ -13,47 +13,34 @@ static uint16_t crc16(uint16_t crc, uint8_t data)
void sdc_init(SDC *sdc)
{
sdc->selected = false;
sdc->initstat = 0;
sdc->recvidx = 0;
sdc->sendidx = -1;
sdc->resp = 0xff;
sdc->fp = NULL;
sdc->cmd17bytes = -1;
sdc->cmd24bytes = -2;
}
// TODO: for now, any nonzero value enables the SDC. To allow
// emulation of systems with multi-devices SPI relay, change
// this.
void sdc_ctl_wr(SDC *sdc, uint8_t val)
byte sdc_spix(SDC *sdc, byte val)
{
sdc->selected = val;
}
void sdc_spi_wr(SDC *sdc, uint8_t val)
{
if (!sdc->selected) {
return;
}
sdc->resp = 0xff;
byte resp = 0xff;
if (sdc->initstat < 8) {
// not woken yet.
sdc->initstat++;
return;
return resp;
}
if (sdc->sendidx >= 0) {
sdc->resp = sdc->sendbuf[sdc->sendidx++];
resp = sdc->sendbuf[sdc->sendidx++];
if (sdc->sendidx == 5) {
sdc->sendidx = -1;
}
return;
return resp;
}
if (sdc->cmd17bytes >= 0) {
if (sdc->fp) {
sdc->resp = getc(sdc->fp);
resp = getc(sdc->fp);
}
sdc->crc16 = crc16(sdc->crc16, sdc->resp);
sdc->crc16 = crc16(sdc->crc16, resp);
sdc->cmd17bytes++;
if (sdc->cmd17bytes == 512) {
sdc->sendbuf[3] = sdc->crc16 >> 8;
@ -61,12 +48,12 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
sdc->sendidx = 3;
sdc->cmd17bytes = -1;
}
return;
return resp;
}
if (sdc->cmd24bytes == -1) {
if (val == 0xff) {
// it's ok to receive idle bytes before the data token.
return;
return resp;
}
if (val == 0xfe) {
// data token, good
@ -75,7 +62,7 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
// something is wrong, cancel cmd24
sdc->cmd24bytes = -2;
}
return;
return resp;
}
if (sdc->cmd24bytes >= 0) {
if (sdc->cmd24bytes < 512) {
@ -102,16 +89,16 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
sdc->cmd24bytes = -3;
}
sdc->cmd24bytes++;
return;
return resp;
}
if ((sdc->recvidx == 0) && ((val > 0x7f) || (val < 0x40))) {
// not a command
return;
return resp;
}
sdc->recvbuf[sdc->recvidx++] = val;
if (sdc->recvidx < 6) {
// incomplete command
return;
return resp;
}
// Command complete
val &= 0x3f;
@ -128,7 +115,7 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
sdc->sendbuf[4] = 0x01;
sdc->sendidx = 4;
}
return;
return resp;
}
if (sdc->initstat == 9) {
// At this stage, we're expecting CMD8 with 0x1aa arg2
@ -143,7 +130,7 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
} else {
sdc-> initstat = 8;
}
return;
return resp;
}
if (sdc->initstat == 10) {
// At this stage, we're expecting CMD55
@ -154,7 +141,7 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
} else {
sdc->initstat = 8;
}
return;
return resp;
}
if (sdc->initstat == 11) {
// At this stage, we're expecting CMD41
@ -165,7 +152,7 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
} else {
sdc->initstat = 8;
}
return;
return resp;
}
// We have a fully initialized card.
if (cmd == 17) {
@ -178,7 +165,7 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
sdc->sendidx = 3;
sdc->cmd17bytes = 0;
sdc->crc16 = 0;
return;
return resp;
}
if (cmd == 24) {
if (sdc->fp) {
@ -188,17 +175,10 @@ void sdc_spi_wr(SDC *sdc, uint8_t val)
sdc->sendidx = 4;
sdc->cmd24bytes = -1;
sdc->crc16 = 0;
return;
return resp;
}
// Simulate success for any unknown command.
sdc->sendbuf[4] = 0x00;
sdc->sendidx = 4;
}
uint8_t sdc_spi_rd(SDC *sdc)
{
if (!sdc->selected) {
return 0xff;
}
return sdc->resp;
return resp;
}

15
emul/z80/sdc.h
View File

@ -1,24 +1,19 @@
#include <stdint.h>
#include <stdbool.h>
#include "emul.h"
typedef struct {
bool selected;
// Initialization status. 0 == not woken 8 == woken 9 == CMD0 received
// 10 == CMD8 received, 11 == CMD55 received, 12 == CMD41 received (fully
// initialized).
unsigned int initstat;
// We receive commands into this buffer.
uint8_t recvbuf[6];
byte recvbuf[6];
// Where the next SPI byte should be stored in recvbuf.
unsigned int recvidx;
// Buffer to the arguments for a response
uint8_t sendbuf[5];
byte sendbuf[5];
// Index of the next byte from sendbuf we should return. If -1, buffer is
// empty.
int sendidx;
// One byte response. When all other response buffers are empty, return
// this.
uint8_t resp;
// File used for contents read/write
FILE *fp;
// number of bytes read into the current CMD17. -1 means no CMD17 active.
@ -31,6 +26,4 @@ typedef struct {
} SDC;
void sdc_init(SDC *sdc);
void sdc_ctl_wr(SDC *sdc, uint8_t val);
void sdc_spi_wr(SDC *sdc, uint8_t val);
uint8_t sdc_spi_rd(SDC *sdc);
byte sdc_spix(SDC *sdc, byte val);

7
emul/z80/sms.c
View File

@ -90,7 +90,8 @@ static void iowr_ports_ctl(uint8_t val)
ports_ctl_wr(&ports, val);
}
static uint8_t iord_sdc_spi()
// TODO: re-add as controller-based SPI
/* static uint8_t iord_sdc_spi()
{
return sdc_spi_rd(&sdc);
}
@ -110,7 +111,7 @@ static uint8_t iord_sdc_ctl()
static void iowr_sdc_ctl(uint8_t val)
{
sdc_ctl_wr(&sdc, val);
}
}*/
void create_window()
{
@ -356,10 +357,12 @@ int main(int argc, char *argv[])
m->iowr[VDP_CMD_PORT] = iowr_vdp_cmd;
m->iowr[VDP_DATA_PORT] = iowr_vdp_data;
m->iowr[PORTS_CTL_PORT] = iowr_ports_ctl;
/* TODO: re-add
m->iord[SDC_SPI] = iord_sdc_spi;
m->iowr[SDC_SPI] = iowr_sdc_spi;
m->iord[SDC_CTL] = iord_sdc_ctl;
m->iowr[SDC_CTL] = iowr_sdc_ctl;
*/
conn = xcb_connect(NULL, NULL);
screen = xcb_setup_roots_iterator(xcb_get_setup(conn)).data;

4
recipes/rc2014/blk/619
View File

@ -1,13 +1,15 @@
0xff00 CONSTANT RS_ADDR 0xfffa CONSTANT PS_ADDR
RS_ADDR 0x80 - CONSTANT SYSVARS
0x8000 CONSTANT HERESTART
4 CONSTANT SPI_DATA 5 CONSTANT SPI_CTL 1 CONSTANT SDC_DEVID
602 LOAD ( acia decl )
5 LOAD ( z80 assembler )
262 LOAD ( xcomp ) 282 LOAD ( boot.z80.decl )
270 LOAD ( xcomp overrides ) 283 335 LOADR ( boot.z80 )
353 LOAD ( xcomp core low ) 603 605 LOADR ( acia )
419 LOAD 423 436 LOADR
390 LOAD ( xcomp core high )
(entry) _
( Update LATEST )
PC ORG @ 8 + !
," ACIA$ " EOT,
," ACIA$ BLK$ " EOT,