emul/sms: add PS/2 keyboard emulation

emul/emul.c

@@ -193,3 +193,6 @@ void emul_printdebug()
     fprintf(stderr, "Min SP: %04x\n", m.minsp);
     fprintf(stderr, "Max IX: %04x\n", m.maxix);
 }
+
+byte iord_noop() { return 0; }
+void iowr_noop(byte val) {}

emul/emul.h

@@ -37,3 +37,6 @@ void emul_trace(ushort addr);
 void emul_memdump();
 void emul_debugstr(char *s);
 void emul_printdebug();
+// use when a port is a NOOP, but it's not an error to access it.
+byte iord_noop();
+void iowr_noop(byte val);

emul/hw/sms/Makefile

@@ -1,5 +1,5 @@
 EXTOBJS = ../../emul.o ../../libz80/libz80.o
-OBJS = sms.o vdp.o port.o pad.o
+OBJS = sms.o vdp.o port.o pad.o kbd.o
 TARGET = sms
 CFLAGS += `pkg-config --cflags xcb`
 LDFLAGS += `pkg-config --libs xcb`

emul/hw/sms/README.md

@@ -25,4 +25,9 @@ pad are:
 * K --> C
 * L --> Start
 
+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.
+
+In both cases (pad or keyboard), only port A emulation is supported.
+
 Press ESC to quit.

emul/hw/sms/kbd.c

@@ -0,0 +1,101 @@
+#include "kbd.h"
+
+void kbd_init(Kbd *kbd, Tristate *TH)
+{
+    kbd->kc = 0;
+    kbd->breaking = false;
+    kbd->TH = TH;
+}
+
+void kbd_pressshift(Kbd *kbd, bool ispressed)
+{
+    kbd->kc = 0x12; // shift keycode
+    kbd->breaking = !ispressed;
+}
+
+void kbd_presskey(Kbd *kbd, uint8_t key)
+{
+    kbd->kc = 0;
+    switch (key) {
+        case '\t': kbd->kc = 0xd; break;
+        case '`': kbd->kc = 0xe; break;
+        case 'q': kbd->kc = 0x15; break;
+        case '1': kbd->kc = 0x16; break;
+        case 'z': kbd->kc = 0x1a; break;
+        case 's': kbd->kc = 0x1b; break;
+        case 'a': kbd->kc = 0x1c; break;
+        case 'w': kbd->kc = 0x1d; break;
+        case '2': kbd->kc = 0x1e; break;
+        case 'c': kbd->kc = 0x21; break;
+        case 'x': kbd->kc = 0x22; break;
+        case 'd': kbd->kc = 0x23; break;
+        case 'e': kbd->kc = 0x24; break;
+        case '4': kbd->kc = 0x25; break;
+        case '3': kbd->kc = 0x26; break;
+        case ' ': kbd->kc = 0x29; break;
+        case 'v': kbd->kc = 0x2a; break;
+        case 'f': kbd->kc = 0x2b; break;
+        case 't': kbd->kc = 0x2c; break;
+        case 'r': kbd->kc = 0x2d; break;
+        case '5': kbd->kc = 0x2e; break;
+        case 'n': kbd->kc = 0x31; break;
+        case 'b': kbd->kc = 0x32; break;
+        case 'h': kbd->kc = 0x33; break;
+        case 'g': kbd->kc = 0x34; break;
+        case 'y': kbd->kc = 0x35; break;
+        case '6': kbd->kc = 0x36; break;
+        case 'm': kbd->kc = 0x3a; break;
+        case 'j': kbd->kc = 0x3b; break;
+        case 'u': kbd->kc = 0x3c; break;
+        case '7': kbd->kc = 0x3d; break;
+        case '8': kbd->kc = 0x3e; break;
+        case ',': kbd->kc = 0x41; break;
+        case 'k': kbd->kc = 0x42; break;
+        case 'i': kbd->kc = 0x43; break;
+        case 'o': kbd->kc = 0x44; break;
+        case '0': kbd->kc = 0x45; break;
+        case '9': kbd->kc = 0x46; break;
+        case '.': kbd->kc = 0x49; break;
+        case '/': kbd->kc = 0x4a; break;
+        case 'l': kbd->kc = 0x4b; break;
+        case ';': kbd->kc = 0x4c; break;
+        case 'p': kbd->kc = 0x4d; break;
+        case '-': kbd->kc = 0x4e; break;
+        case '\'': kbd->kc = 0x52; break;
+        case '[': kbd->kc = 0x54; break;
+        case '=': kbd->kc = 0x55; break;
+        case '\r': kbd->kc = 0x5a; break;
+        case ']': kbd->kc = 0x5b; break;
+        case '\\': kbd->kc = 0x5d; break;
+        case '\b': kbd->kc = 0x66; break;
+    }
+}
+
+uint8_t kbd_rd(Kbd *kbd)
+{
+    // There are 3 modes for reading the kbd:
+    // 1. TH = highz: we're polling the the existence of a KC
+    // 2. TH = low: return low nibble
+    // 3. TH = high: return high nibble and reset KC
+    uint8_t res = 0;
+    uint8_t tosend = kbd->kc;
+    if (kbd->breaking) {
+        tosend = 0xf0;
+    }
+    if (*kbd->TH == TRI_HIGHZ) { // polling
+        if (!kbd->kc) {
+            res = 0x10; // indicate KC absence;
+        }
+    } else if (*kbd->TH == TRI_LOW) { // TH selected
+        res = tosend & 0xf;
+    } else {
+        res = tosend >> 4;
+        if (kbd->breaking) {
+            kbd->breaking = false;
+        } else {
+            kbd->kc = 0;
+        }
+    }
+    return res;
+}
+

emul/hw/sms/kbd.h

@@ -0,0 +1,16 @@
+#include <stdint.h>
+#include <stdbool.h>
+#include "port.h"
+
+#define KBD_BUFSZ 0x10
+
+typedef struct {
+    uint8_t kc; // last keycode to be pressed. 0 means none.
+    bool breaking; // whether we should send 0xf0 before kc
+    Tristate *TH;
+} Kbd;
+
+void kbd_init(Kbd *kbd, Tristate *TH);
+void kbd_pressshift(Kbd *kbd, bool ispressed);
+void kbd_presskey(Kbd *kbd, uint8_t keycode);
+uint8_t kbd_rd(Kbd *kbd);

emul/hw/sms/sms.c

@@ -11,6 +11,7 @@
 #include "vdp.h"
 #include "port.h"
 #include "pad.h"
+#include "kbd.h"
 
 #define RAMSTART 0xc000
 #define VDP_CMD_PORT 0xbf
@@ -36,6 +37,8 @@ static VDP vdp;
 static bool vdp_changed;
 static Ports ports;
 static Pad pad;
+static Kbd kbd;
+static bool use_kbd = false;
 
 static uint8_t iord_vdp_cmd()
 {
@@ -62,6 +65,11 @@ static uint8_t iord_pad()
     return pad_rd(&pad);
 }
 
+static uint8_t iord_kbd()
+{
+    return kbd_rd(&kbd);
+}
+
 static void iowr_vdp_cmd(uint8_t val)
 {
     vdp_cmd_wr(&vdp, val);
@@ -159,14 +167,24 @@ void draw_pixels()
 static bool _handle_keypress(xcb_generic_event_t *e)
 {
     xcb_key_press_event_t *ev = (xcb_key_press_event_t *)e;
+    if (ev->detail == 0x09) { // ESC
+        return true;
+    }
     bool ispressed = e->response_type == XCB_KEY_PRESS;
     // change keycode into symbol
     xcb_get_keyboard_mapping_reply_t* km = xcb_get_keyboard_mapping_reply(
         conn, xcb_get_keyboard_mapping(conn, ev->detail, 1), NULL);
     if (km->length) {
         xcb_keysym_t* keysyms = (xcb_keysym_t*)(km + 1);
+        if (use_kbd) {
+            if ((keysyms[0] == XK_Shift_L) || (keysyms[0] == XK_Shift_R)) {
+                kbd_pressshift(&kbd, ispressed);
+            } else if (ispressed) {
+                fprintf(stderr, "pressing %x\n", keysyms[0]);
+                kbd_presskey(&kbd, keysyms[0]);
+            }
+        } else { // pad
             switch (keysyms[0]) {
-            case XK_Escape: free(km); return true;
                 case 'w':
                     pad_setbtn(&pad, PAD_BTN_UP, ispressed);
                     break;
@@ -193,6 +211,7 @@ static bool _handle_keypress(xcb_generic_event_t *e)
                     break;
             }
         }
+    }
     free(km);
     return false;
 }
@@ -242,13 +261,30 @@ void event_loop()
     }
 }
 
+static void usage()
+{
+    fprintf(stderr, "Usage: ./sms [-k] /path/to/rom\n");
+}
+
 int main(int argc, char *argv[])
 {
-    if (argc != 2) {
-        fprintf(stderr, "Usage: ./sms /path/to/rom\n");
+    if (argc < 2) {
+        usage();
         return 1;
     }
-    FILE *fp = fopen(argv[1], "r");
+    int ch;
+    while ((ch = getopt(argc, argv, "k")) != -1) {
+        switch (ch) {
+            case 'k':
+                use_kbd = true;
+                break;
+        }
+    }
+    if (optind != argc-1) {
+        usage();
+        return 1;
+    }
+    FILE *fp = fopen(argv[optind], "r");
     if (fp == NULL) {
         fprintf(stderr, "Can't open %s\n", argv[1]);
         return 1;
@@ -268,12 +304,18 @@ int main(int argc, char *argv[])
     vdp_init(&vdp);
     vdp_changed = false;
     ports_init(&ports);
-    ports.portA_rd = iord_pad;
     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;
     m->iord[PORTS_IO2_PORT] = iord_ports_io2;
+    m->iord[PORTS_CTL_PORT] = iord_noop;
     m->iowr[VDP_CMD_PORT] = iowr_vdp_cmd;
     m->iowr[VDP_DATA_PORT] = iowr_vdp_data;
     m->iowr[PORTS_CTL_PORT] = iowr_ports_ctl;

recipes/sms/kbd.md

@@ -105,7 +105,7 @@ to TH (and also the A/B on the '157). Q is hooked to PB0 and TL.
 We start with the base recipe and add a few things:
 
 1. at the top: `SYSVARS 0x72 + CONSTANT PS2_MEM`
-2. After VDP load: `641 LOAD : (ps2kc) (ps2kcB) ;` (that binds us to port B)
+2. After VDP load: `621 LOAD : (ps2kc) (ps2kcB) ;` (that binds us to port B)
 3. Right after: `411 414 LOADR` (that gives us `(key)`)
 4. After `VDP$`: `PS2$`.