added PAL/NTSC detection

c64/basic/basic_cold_start.s

@@ -17,6 +17,14 @@ startup_banner:
 
 	`TARGET_HOOK_BANNER
 
+	;; Print PAL/NTSC
+	ldx #30 ; NTSC
+	lda PALNTSC
+	beq +
+	ldx #31 ; PAL
+*
+	jsr print_packed_message
+
 	;; Work out free bytes, and display
 	jsr basic_do_new
 	lda basic_top_of_memory_ptr+0
@@ -26,7 +34,7 @@ startup_banner:
 	lda basic_top_of_memory_ptr+1
 	sbc basic_end_of_text_ptr+1
 
-	jsr print_integer	
+	jsr print_integer
 
 	lda #$20
 	jsr JCHROUT
@@ -37,8 +45,8 @@ startup_banner:
 
 	;; jump into warm start loop
 	jmp basic_warm_start
-	
-	
+
+
 startup_message:
 	;; Clear the screen
 	.byte $93

c64/kernal/cint.s

@@ -14,7 +14,32 @@ cint:
 cint_brk: ; entry for BRK and STOP+RESTORE - XXX, where should it start?
 
 	jsr setup_vicii
-	
+
+	;; Detect video system (PAL/NTSC), use Graham's method, as it's short and reliable
+	;; see here: https://codebase64.org/doku.php?id=base:detect_pal_ntsc
+
+cint_w0:
+	lda VIC_RASTER
+cint_w1:
+	cmp VIC_RASTER
+    beq cint_w1
+    bmi cint_w0
+
+	;; Result in A, if no interrupt happened during the test:
+	;; #$37 -> 312 rasterlines, PAL,  VIC 6569
+	;; #$06 -> 263 rasterlines, NTSC, VIC 6567R8
+	;; #$05 -> 262 rasterlines, NTSC, VIC 6567R56A
+
+	cmp #$07
+	bcs cint_pal
+cint_ntsc:
+	lda #$00
+	beq +
+cint_pal:
+	lda #$01
+*
+	sta PALNTSC
+
 	;; Initialise cursor blink flags  (Compute's Mapping the 64 p215)
 	lda #$00
 	sta cursor_blink_disable
@@ -51,4 +76,3 @@ cint_brk: ; entry for BRK and STOP+RESTORE - XXX, where should it start?
 
 	;; Fallthrough/jump to screen clear routine (Compute's Mapping the 64 p215)
 	jmp clear_screen
-