function keys, RUN and HELP are now programmable at compile time

c64/kernal/chrin_real.s

@@ -91,10 +91,10 @@ read_from_keyboard:
 	cmp #$0D
 	bne not_enter
 
+chrin_enter:
+
 	jsr cursor_disable
-
 	jsr pop_keyboard_buffer
-
 	jsr cursor_hide_if_visible
 
 	// It was enter.
@@ -140,12 +140,45 @@ empty_line:
 
 not_enter:
 
-	// Print character
 	lda KEYD
-	// XXX add support for SHIFT + RUN/STOP ($84) and function keys (should be configurable)
-	jsr CHROUT
 
+#if CONFIG_PROGRAMMABLE_KEYS
+
+	ldx #(__programmable_keys_codes_end - programmable_keys_codes - 1)
+
+chrin_programmable_loop:
+
+	cmp programmable_keys_codes, x
+	beq chrin_programmable_key
+	dex
+	bpl chrin_programmable_loop
+
+	// FALLTROUGH
+
+#endif // CONFIG_PROGRAMMABLE_KEYS
+
+chrin_print_character:
+
+	jsr CHROUT
 	jsr pop_keyboard_buffer
 
 	// Keep looking for input from keyboard until carriage return
 	jmp chrin_repeat
+
+#if CONFIG_PROGRAMMABLE_KEYS
+
+chrin_programmable_key:
+
+	// .X contains index of the key code, we need offset to key string instead
+	lda programmable_keys_offsets, x
+	tax
+
+	// Print all the characters assigned to key
+!:
+	lda programmable_keys_strings, x
+	beq chrin_enter
+	jsr CHROUT // our implementation preserves .X too
+	inx
+	bne !-     // jumps always
+
+#endif // CONFIG_PROGRAMMABLE_KEYS