Add KIM-1 functions to write to the 7-segment LED display and get

keypresses from the keypad.
Includes sample program illustrating how to use them.
Tested on real KIM-1 hardware.

asminc/kim1.inc

@@ -16,6 +16,10 @@ INTCHR   := $1E5A     ; Input character without case conversion
 DUMPT    := $1800     ; Dump memory to tape
 LOADT    := $1873     ; Load memory from tape
 START    := $1C4F     ; Enter KIM-1 monitor
+SCANDS   := $1F1F     ; Scan 7-segment display
+KEYIN    := $1F40     ; Open up keyboard channel
+GETKEY   := $1F6A     ; Return key from keyboard
+
 
 ; ---------------------------------------------------------------------------
 ; System Memory

include/kim1.h

@@ -56,5 +56,18 @@ int __fastcall__ loadt (unsigned char);
 /* Write to tape */
 int __fastcall__ dumpt (unsigned char, const void*, const void*);
 
+
+/* Write to 7-segment LED display. Due to hardware limitations it only
+** displays briefly, so must be called repeatedly to update the
+** display.
+**/
+void __fastcall__ scandisplay(unsigned char left, unsigned char middle, unsigned char right);
+
+/*
+** Get a keypress from the keypad. Returns $00-$0F(0-F), $10(AD), $11(DA), $12(+),
+** $13(GO), $14(PC) or $15 for no keypress.
+**/
+int __fastcall__ getkey();
+
 /* End of sym1.h */
 #endif

libsrc/kim1/getkey.s

@@ -0,0 +1,18 @@
+;
+; int __fastcall__ getkey();
+;
+
+.include        "kim1.inc"
+
+.import         popa
+
+.export         _getkey
+
+.proc           _getkey
+
+        jsr     KEYIN           ; Open up keyboard channel
+        jsr     GETKEY          ; Get key code
+        ldx     #0              ; MSB of return value is zero
+        rts
+
+.endproc

libsrc/kim1/scandisplay.s

@@ -0,0 +1,21 @@
+;
+; void __fastcall__ scandisplay(unsigned char left, unsigned char middle, unsigned char right);
+;
+
+.include        "kim1.inc"
+
+.import         popa
+
+.export         _scandisplay
+
+.proc           _scandisplay
+
+        sta     $F9             ; Rightmost display data
+        jsr     popa
+        sta     $FA             ; Middle display data
+        jsr     popa
+        sta     $FB             ; Leftmost display data
+        jsr     SCANDS
+        rts
+
+.endproc

samples/kim1/kimKeyDisp.c

@@ -0,0 +1,52 @@
+/* Example illustrating scandisplay() and getkey() functions. */
+
+#include <stdio.h>
+#include <kim1.h>
+
+int main (void)
+{
+    int i, j, k, l;
+    int last = 15;
+
+    printf("\nKIM-1 Demo\n");
+
+    for (i = 0; i < 16; i++) {
+        for (j = 0; j < 16; j++) {
+            for (k = 0; k < 16; k++) {
+                scandisplay(i, j, k);
+
+                l = getkey();
+
+                if (l != last) {
+                    switch (l) {
+                    case 0x0: case 0x1: case 0x2: case 0x3:
+                    case 0x4: case 0x5: case 0x6: case 0x7:
+                    case 0x8: case 0x9: case 0xa: case 0xb:
+                    case 0xc: case 0xd: case 0xe: case 0xf:
+                        printf("Key pressed: %X\n", l);
+                        break;
+                    case 0x10:
+                        printf("Key pressed: AD\n");
+                        break;
+                    case 0x11:
+                        printf("Key pressed: DA\n");
+                        break;
+                    case 0x12:
+                        printf("Key pressed: +\n");
+                        break;
+                    case 0x13:
+                        printf("Key pressed: GO\n");
+                        break;
+                    case 0x14:
+                        printf("Key pressed: PC\n");
+                        break;
+                    }
+
+                    last = l;
+                }
+            }
+        }
+    }
+
+    return 0;
+}