From cdfebce9c34e3116457a7c28e3eb60000d65d7e6 Mon Sep 17 00:00:00 2001
From: Miquel Sabaté Solà <mikisabate@gmail.com>
Date: Fri, 14 Mar 2025 16:31:43 +0100
Subject: Support PAL natively
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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>
---
 Makefile     | 22 ++++++++++++++++------
 src/jetpac.s | 30 ++++++++++++++++++++++++++----
 src/title.s  |  2 +-
 3 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/Makefile b/Makefile
index cd212d1..d693d23 100644
--- a/Makefile
+++ b/Makefile
@@ -28,20 +28,30 @@ deps:
 	@which $(CC65) >/dev/null 2>/dev/null || (echo "ERROR: $(CC65) not found." && false)
 
 .PHONY: build
-build: build-full build-partial
+build: build-full build-partial build-pal
 
 .PHONY: build-full
 build-full:
 	$(Q) rm -f config/generated.s
-	$(Q) touch config/generated.s
+	$(Q) echo "HZ = 60" >> config/generated.s
 
-	$(E) "	CC	 jetpac (full)"
-	$(Q) $(CC65) $(CCOPTS) src/jetpac.s -C config/nrom.cfg -o out/jetpac.nes
+	$(E) "	CC	 jetpac (full, NTSC)"
+	$(Q) $(CC65) $(CCOPTS) src/jetpac.s -C config/nrom.cfg -o "out/Jetpac (NTSC).nes"
 
 .PHONY: build-partial
 build-partial:
 	$(Q) rm -f config/generated.s
 	$(Q) echo "PARTIAL = 1"  >> config/generated.s
+	$(Q) echo "HZ = 60" >> config/generated.s
 
-	$(E) "	CC	 jetpac (partial)"
-	$(Q) $(CC65) $(CCOPTS) src/jetpac.s -C config/nrom.cfg -Wa -DPARTIAL=1 -o out/partial.nes
+	$(E) "	CC	 jetpac (partial, NTSC)"
+	$(Q) $(CC65) $(CCOPTS) src/jetpac.s -C config/nrom.cfg -o "out/Jetpac (DEV).nes"
+
+.PHONY: build-pal
+build-pal:
+	$(Q) rm -f config/generated.s
+	$(Q) echo "PAL = 1"  >> config/generated.s
+	$(Q) echo "HZ = 50" >> config/generated.s
+
+	$(E) "	CC	 jetpac (PAL)"
+	$(Q) $(CC65) $(CCOPTS) src/jetpac.s -C config/nrom.cfg -o "out/Jetpac (PAL).nes"
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.
-- 
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