Support PAL natively

Also add a make target specific for a PAL version, even if only the full
game will be built, not the development "partial" one.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

2 files changed, 27 insertions, 5 deletions

diff --git a/src/jetpac.s b/src/jetpac.s
index 8acbb4e..d3eef5a 100644
--- a/src/jetpac.s
+++ b/src/jetpac.s
@@ -1,12 +1,34 @@
+;; NOTE: automatically generated by the build system.
+.include "../config/generated.s"
+
 .segment "HEADER"
+    ;; Bytes 0-3: NES\0 magic header.
     .byte 'N', 'E', 'S', $1A
+
+    ;; Standard 32KB + 8KB NROM cartridge.
     .byte $02, $01
-    .res $0A, $00
 
-.segment "CODE"
+    ;; Horizontal mirroring, no battery.
+    .byte $00
 
-;; NOTE: automatically generated by the build system.
-.include "../config/generated.s"
+    ;; We use the NES 2.0 header mainly to differentiate between NTSC vs PAL in
+    ;; a way that emulators won't ignore it.
+    .byte $08
+
+    ;; Blanked out stuff.
+    .res $04, $00
+
+    ;; NTSC vs PAL
+    .ifdef PAL
+        .byte $01
+    .else
+        .byte $00
+    .endif
+
+    ;; Blanked out stuff.
+    .res $03, $00
+
+.segment "CODE"
 
 .include "../include/apu.s"
 .include "../include/oam.s"
diff --git a/src/title.s b/src/title.s
index db627ae..3e6da61 100644
--- a/src/title.s
+++ b/src/title.s
@@ -8,7 +8,7 @@
     SPRITE_X_POSITION  = $40
 
     ;; The title has a timer as a delay between joypad presses from the player.
-    TIMER_INIT_VALUE = 20
+    TIMER_INIT_VALUE = (HZ / 3)
     zp_title_timer = $30
 
     ;; Initialize all the elements for the title screen.