emul/z80: add SD card support to SMS

It works (in emulation, but soon on real hardware!), but the LIST
command is awkward due to tight screen estate...

blk/001

@@ -6,6 +6,6 @@ MASTER INDEX
 160 AVR SPI programmer
 170-259 unused                260 Cross compilation
 280 Z80 boot code             350 Core words
-410 PS/2 keyboard subsystem   420 SD Card subsystem
-440 8086 boot code
+410 PS/2 keyboard subsystem   418 Z80 SPI Relay driver
+420 SD Card subsystem         440 8086 boot code
 470-519 unused                520 Fonts

blk/418

@@ -7,4 +7,4 @@ to SPI_CTL, we expect a bitmask of the device to select, with
 returns 0 if the device is ready or 1 if it's still running an
 exchange. Writing to SPI_DATA initiates an exchange.
 
-Provides the SPI relay protocol. Load driver with "596 LOAD".
+Provides the SPI relay protocol. Load driver with "419 LOAD".

emul/z80/Makefile

@@ -1,7 +1,7 @@
 TARGETS = forth rc2014 sms ti84
 OBJS = emul.o z80.o
 RC2014_OBJS = $(OBJS) sio.o acia.o sdc.o
-SMS_OBJS = $(OBJS) sms_vdp.o sms_ports.o sms_pad.o ps2_kbd.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
 STAGE = $(CDIR)/stage

emul/z80/README.md

@@ -61,6 +61,8 @@ pad are:
 If your ROM is configured with PS/2 keyboard input, run this emulator with the
 `-k` flag to replace SMS pad emulation with keyboard emulation.
 
+The `-c` option connects a SD card in the same way as the RC2014 emulator.
+
 In both cases (pad or keyboard), only port A emulation is supported.
 
 Press ESC to quit.

emul/z80/rc2014.c

@@ -143,6 +143,10 @@ int main(int argc, char *argv[])
             case 'c':
                 fprintf(stderr, "Setting up SD card image with %s\n", optarg);
                 sdc.fp = fopen(optarg, "r+");
+                if (sdc.fp == NULL) {
+                    fprintf(stderr, "Can't open file\n");
+                    return 1;
+                }
                 break;
         }
     }

emul/z80/sms.c

@@ -12,6 +12,7 @@
 #include "sms_ports.h"
 #include "sms_pad.h"
 #include "ps2_kbd.h"
+#include "sdc.h"
 
 #define RAMSTART 0xc000
 #define VDP_CMD_PORT 0xbf
@@ -19,6 +20,8 @@
 #define PORTS_CTL_PORT 0x3f
 #define PORTS_IO1_PORT 0xdc
 #define PORTS_IO2_PORT 0xdd
+#define SDC_CTL 0x05
+#define SDC_SPI 0x04
 #define MAX_ROMSIZE 0x8000
 
 static xcb_connection_t    *conn;
@@ -39,6 +42,7 @@ static Ports ports;
 static Pad pad;
 static Kbd kbd;
 static bool use_kbd = false;
+static SDC sdc;
 
 static uint8_t iord_vdp_cmd()
 {
@@ -86,6 +90,28 @@ static void iowr_ports_ctl(uint8_t val)
     ports_ctl_wr(&ports, val);
 }
 
+static uint8_t iord_sdc_spi()
+{
+    return sdc_spi_rd(&sdc);
+}
+
+static void iowr_sdc_spi(uint8_t val)
+{
+    sdc_spi_wr(&sdc, val);
+}
+
+// in emulation, exchanges are always instantaneous, so we
+// always report as ready.
+static uint8_t iord_sdc_ctl()
+{
+    return 0;
+}
+
+static void iowr_sdc_ctl(uint8_t val)
+{
+    sdc_ctl_wr(&sdc, val);
+}
+
 void create_window()
 {
     uint32_t mask;
@@ -227,7 +253,7 @@ void event_loop()
         if (vdp_changed) {
             // To avoid overdrawing, we'll let the CPU run a bit to finish its
             // drawing operation.
-            emul_steps(100);
+            emul_steps(10000);
             draw_pixels();
         }
         // A low tech way of checking when the window was closed. The proper way
@@ -263,7 +289,7 @@ void event_loop()
 
 static void usage()
 {
-    fprintf(stderr, "Usage: ./sms [-k] /path/to/rom\n");
+    fprintf(stderr, "Usage: ./sms [-k] [-c sdcard.img] /path/to/rom\n");
 }
 
 int main(int argc, char *argv[])
@@ -272,12 +298,27 @@ int main(int argc, char *argv[])
         usage();
         return 1;
     }
+    vdp_init(&vdp);
+    vdp_changed = false;
+    ports_init(&ports);
+    pad_init(&pad, &ports.THA);
+    kbd_init(&kbd, &ports.THA);
+    sdc_init(&sdc);
+
     int ch;
-    while ((ch = getopt(argc, argv, "k")) != -1) {
+    while ((ch = getopt(argc, argv, "kc:")) != -1) {
         switch (ch) {
             case 'k':
                 use_kbd = true;
                 break;
+            case 'c':
+                fprintf(stderr, "Setting up SD card image with %s\n", optarg);
+                sdc.fp = fopen(optarg, "r+");
+                if (sdc.fp == NULL) {
+                    fprintf(stderr, "Can't open file\n");
+                    return 1;
+                }
+                break;
         }
     }
     if (optind != argc-1) {
@@ -301,16 +342,12 @@ int main(int argc, char *argv[])
         fprintf(stderr, "ROM image too large.\n");
         return 1;
     }
-    vdp_init(&vdp);
-    vdp_changed = false;
-    ports_init(&ports);
-    pad_init(&pad, &ports.THA);
-    kbd_init(&kbd, &ports.THA);
     if (use_kbd) {
         ports.portA_rd = iord_kbd;
     } else {
         ports.portA_rd = iord_pad;
     }
+
     m->iord[VDP_CMD_PORT] = iord_vdp_cmd;
     m->iord[VDP_DATA_PORT] = iord_vdp_data;
     m->iord[PORTS_IO1_PORT] = iord_ports_io1;
@@ -319,11 +356,19 @@ 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;
+    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;
     create_window();
     draw_pixels();
     event_loop();
     emul_printdebug();
+    if (sdc.fp) {
+        fclose(sdc.fp);
+    }
     return 0;
 }

recipes/rc2014/sdcard.md

@@ -84,7 +84,7 @@ and `SPI_CTL`,  which are respectively `4` and `5` in our relay design.
 You also need to tell the SDC subsystem which SPI device to activate by defining
 the `SDC_DEVID` (1, 2, 4, 8 for device 0, 1, 2 or 3)
 
-You can then load the driver with `616 LOAD`. This driver provides
+You can then load the driver with `419 LOAD`. This driver provides
 `(spix)` and `(spie)` which are then used in the SDC driver.
 
 The SDC driver is at B420. It gives you a load range. This means that what