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-rw-r--r--.gitignore2
-rw-r--r--CHANGELOG.md3
-rw-r--r--CONTRIBUTING.md37
-rw-r--r--LICENSE674
-rw-r--r--Makefile38
-rw-r--r--README.md41
-rw-r--r--assets/jetpac.chrbin0 -> 8192 bytes
-rw-r--r--assets/session.nss613
-rw-r--r--config/nrom.cfg24
-rw-r--r--include/apu.s4
-rw-r--r--include/globals.s34
-rw-r--r--include/oam.s11
-rw-r--r--include/ppu.s8
-rw-r--r--src/jetpac.s86
-rw-r--r--src/vectors.s109
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diff --git a/.gitignore b/.gitignore
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+out/
+TODO
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
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--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,3 @@
+# 1.0
+
+WIP
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
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--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,37 @@
+## Why?
+
+Do you want to fix an error you have found? Do you know a way to improve my
+6502-fu or do you know a technique on NES/Famicom development that might help
+here? I am open for discussion and welcome any help!
+
+## How?
+
+There are many ways to help me out. One way might be to open an issue on
+[Github's tracker](https://github.com/mssola/jetpac.nes/issues) and start a
+discussion. For this, mind the following:
+
+- Check that the issue has not already been reported or fixed in `main`.
+- Try to be concise and precise in your description.
+- If you have found a problem, provide a step by step guide on how to reproduce it.
+- Provide the version you are using (git commit SHA), as well as the version of
+ the toolchain and the emulator/system being used.
+
+Another way is to simply submit a pull request. For this, also mind these:
+
+- Write a [good commit message](https://chris.beams.io/posts/git-commit/).
+- You are sure that `make` continues to work.
+- The game continues to work.
+- The pull request has *only* one subject and a clear title. You are not
+ submitting a pull request with tons of different unrelated commits.
+
+## Development cycle
+
+In order to test your changes, I'd go this way:
+
+1. Make sure that you have the toolchain installed. For this you can call `make
+ deps` and it will error out if you are missing anything.
+2. Make your changes in the code and run `make`. This will produce the ROM
+ inside of the `out` directory.
+3. Run the ROM that was produced with an emulator of your choosing. Make sure
+ that things run as expected.
+
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..f288702
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,674 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
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+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+ 13. Use with the GNU Affero General Public License.
+
+ Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work. The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+ 14. Revised Versions of this License.
+
+ The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation. If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+ If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+ Later license versions may give you additional or different
+permissions. However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+ 15. Disclaimer of Warranty.
+
+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+ 16. Limitation of Liability.
+
+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of author>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ <program> Copyright (C) <year> <name of author>
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..4130ebf
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,38 @@
+V =
+ifeq ($(strip $(V)),)
+ E = @echo
+ Q = @
+else
+ E = @\#
+ Q =
+endif
+
+CC65 ?= cl65
+CCOPTS ?= --target nes
+
+.PHONY: all
+all: clean deps build
+
+.PHONY: clean
+clean:
+ @rm -rf out
+ @find . -type f -name "*.o" -delete
+ @find . -type f -name "*.nes" -delete
+ @mkdir -p out/
+
+.PHONY: deps
+deps:
+ @which $(CC65) >/dev/null 2>/dev/null || (echo "ERROR: $(CC65) not found." && false)
+
+.PHONY: build
+build: build-full build-partial
+
+.PHONY: build-full
+build-full:
+ $(E) " CC jetpac (full)"
+ $(Q) $(CC65) $(CCOPTS) src/jetpac.s -C config/nrom.cfg -o out/jetpac.nes
+
+.PHONY: build-partial
+build-partial:
+ $(E) " CC jetpac (partial)"
+ $(Q) $(CC65) $(CCOPTS) src/jetpac.s -C config/nrom.cfg --asm-define PARTIAL=1 -o out/partial.nes
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..e0bfa31
--- /dev/null
+++ b/README.md
@@ -0,0 +1,41 @@
+This is a port to the NES of the renown
+[jetpac](https://en.wikipedia.org/wiki/Jetpac) game from Ultimate Play the Game.
+You can find a ROM to play the game in the [releases
+page](https://github.com/mssola/jetpac.nes/releases).
+
+## The game
+
+The game follows the original as much as possible. Some things had to be adapted
+because of hardware differences. For example, the colors are a bit different
+because the NES offers a fixed set of them and that's it. Other than small
+differences I'm sure that the feel from the game might be a bit different too.
+Some of it might be attributed to, again, the nature of the NES, but some other
+bit of this can be attributed directly to me. Hence, if you know how to improve
+the game (by being closer to the original), [do tell me](./CONTRIBUTING.md)!
+
+Other than that, the game is a shooter in which you have to re-assemble your
+ship's parts and fill it with fuel, all while killing enemies that keep popping
+up. The controls are as follows:
+
+| Button | Action |
+|:----------------------------------------------:|:----------------------|
+| <kbd>Start</kbd> | Pause/Resume the game |
+| <kbd>Select</kbd> | *Not used* |
+| <kbd>A</kbd> | Throttle |
+| <kbd>B</kbd> | Shoot |
+| <kbd>Arrow Left</kbd> & <kbd>Arrow Right</kbd> | Move horizontally |
+| <kbd>Arrow up</kbd> | Throttle |
+| <kbd>Arrow down</kbd> | *Not used* |
+
+## [Changelog](https://pbs.twimg.com/media/DJDYCcLXcAA_eIo?format=jpg&name=small)
+
+Read the [CHANGELOG.md](./CHANGELOG.md) file.
+
+## License
+
+The original game was developed and published by Ultimate Play the Game and
+released for the ZX Spectrum and VIC-20 in 1983 and the BBC Micro in 1984. Thus,
+the original idea is not mine, and I only did the porting to the NES/Famicom
+platform. This port is released under the
+[GPLv3+](http://www.gnu.org/licenses/gpl-3.0.txt), Copyright (C) 2023-<i>Ω</i>
+Miquel Sabaté Solà.
diff --git a/assets/jetpac.chr b/assets/jetpac.chr
new file mode 100644
index 0000000..2eae737
--- /dev/null
+++ b/assets/jetpac.chr
Binary files differ
diff --git a/assets/session.nss b/assets/session.nss
new file mode 100644
index 0000000..769acad
--- /dev/null
+++ b/assets/session.nss
@@ -0,0 +1,613 @@
+NSTssTXT
+
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+propertyCHRlabel7=global condition
+
+
+
+MetaSpriteBankName=session
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+
+FilterCHR=0
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+FileNameCHR=C:\users\mssola\Desktop\jetpac-sprites
+FileNameName=C:\users\mssola\Desktop\asd
+FileNamePal=
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+RadioAutoexport_UseWorkDir=0
+RadioAutoexport_UseSubDir_Project=0
+RadioAutoexport_UseSubDir_NEXXT=0
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+
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+
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+
+
+BrushMask_3a=000100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100[2]0100010001000100[2]010001000100
+
+
+BrushMask_4a=0001[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00[2]01[2]00
+
+
+BrushMask_5a=0001[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[3]01[3]00[2]01[3]00[2]01[3]00[2]
+
+
+BrushMask_6a=01[100]
+
+
+BrushMask_7a=01[100]
+
+
+BrushMask_8a=01[100]
+
+
+BrushMask_2b=00[5]01[6]00[8]01[2]00[6]01[2]00[5]0100[a]0100[3]0100[c]0100[2]0100[c]01000100[e]01[2]00[e]01[2]00[e]01[2]00[e]01[2]00[e]01[2]00[e]01000100[c]0100[2]0100[c]0100[3]0100[a]0100[5]01[2]00[6]01[2]00[8]01[6]00[5]
+
+
+BrushMask_3b=000100[e]01[3]00[e]0100[de]
+
+
+BrushMask_4b=0001[2]00[d]01[4]00[c]01[4]00[d]01[2]00[cd]
+
+
+BrushMask_5b=0001[3]00[c]01[5]00[b]01[5]00[b]01[5]00[c]01[3]00[bc]
+
+
+BrushMask_6b=00[2]01[2]00[d]01[4]00[b]01[6]00[a]01[6]00[b]01[4]00[d]01[2]00[ac]
+
+
+BrushMask_7b=00[2]01[3]00[c]01[5]00[a]01[7]00[9]01[7]00[9]01[7]00[a]01[5]00[c]01[3]00[9b]
+
+
+BrushMask_8b=00[2]01[4]00[b]01[6]00[9]01[8]00[8]01[8]00[8]01[8]00[8]01[8]00[9]01[6]00[b]01[4]00[8a]
+
+
+32_BankViewTable=00000000[100]00001000[100]00002000[100]00003000[100]
+
+
+32_BankViewTableUndo=00000000[100]00001000[100]00002000[100]00003000[100]
+
+
+8_TileCollisionProperties=00[400]
+
+
+8_TileCollisionPropertiesUndo=00[400]
+
+
+PropertyConditions=1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]
+
+
+PropertyConditionsUndo=1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]1[2]0[2]
+
+
+TilePropConditionType=00[7]02
+
+
+TilePropConditionTypeUndo=00[7]02
+
+
+MetatileSet_2x2_id=00[400]
+
+
+MetatileSet_2x2_idUndo=00[400]
+
+
+MetatileSet_2x2_pal=00[400]
+
+
+MetatileSet_2x2_palUndo=00[400]
+
+
+MetatileSet_2x2_props=00[400]
+
+
+MetatileSet_2x2_propsUndo=00[400]
+
+
+MetatileSet_4x4_id=00[1000]
+
+
+MetatileSet_4x4_idUndo=00[1000]
+
+
+MetatileSet_4x4_pal=00[1000]
+
+
+MetatileSet_4x4_palUndo=00[1000]
+
+
+MetatileSet_4x4_props=00[1000]
+
+
+MetatileSet_4x4_propsUndo=00[1000]
+
+
+MetatileSet_8x8_id=00[2000]
+
+
+MetatileSet_8x8_idUndo=00[2000]
+
+
+MetatileSet_8x8_pal=00[2000]
+
+
+MetatileSet_8x8_palUndo=00[2000]
+
+
+MetatileSet_8x8_props=00[2000]
+
+
+MetatileSet_8x8_propsUndo=00[2000]
+
+
+MetatileSetLabels_2x2=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+MetatileSetLabels_2x2Undo=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+MetatileSetLabels_4x4=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+MetatileSetLabels_4x4Undo=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+MetatileSetLabels_8x8=Unlabeled,Unlabeled
+MetatileSetLabels_8x8Undo=Unlabeled,Unlabeled
+
+CHRBankLabels=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+CHRBankLabelsUndo=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+32_NTSC_MsprDuration=00000006[100]
+
+
+32_NTSC_MsprDurationUndo=00000006[100]
+
+
+32_PAL_MsprDuration=00000005[100]
+
+
+32_PAL_MsprDurationUndo=00000005[100]
+
+
+MsprDirectTagStart=[100]
+
+
+MsprDirectTagStartUndo=[100]
+
+
+MsprDirectTagLoop=[100]
+
+
+MsprDirectTagLoopUndo=[100]
+
+
+MsprDirectTagCall=[100]
+
+
+MsprDirectTagCallUndo=[100]
+
+
+MsprDirectTagCall2=[100]
+
+
+MsprDirectTagCall2Undo=[100]
+
+
+MsprDirectTagRevert=[100]
+
+
+MsprDirectTagRevertUndo=[100]
+
+
+MsprDirectTagSeconds=[100]
+
+
+MsprDirectTagSecondsUndo=[100]
+
+
+MsprDirectTagHalfSeconds=[100]
+
+
+MsprDirectTagHalfSecondsUndo=[100]
+
+
+Checkpoint_Palette=0f0010300f0c21320f0516270f0b1a290f1c21320f1122330f1223340f1324350f1324360f1526370f1627370f1928380f1829380f1b2a390f1b2b3c0f1c2c3b
+
+
+Checkpoint_PalUndo=0f0010300f0c21320f0516270f0b1a290f1c21320f1122330f1223340f1324350f1324360f1526370f1627370f1928380f1829380f1b2a390f1b2b3c0f1c2c3b
+
+
+Checkpoint_CHRMain=00[4000]
+
+
+Checkpoint_CHRUndo=00[4000]
+
+
+Checkpoint_NameTable=00[3c0]
+
+
+Checkpoint_NameUndo=00[3c0]
+
+
+Checkpoint_AttrTable=00[40]
+
+
+Checkpoint_AttrUndo=00[40]
+
+
+Checkpoint_MetaSprites=ff[10000]
+
+
+Checkpoint_32_BankViewTable=00000000[100]00001000[100]00002000[100]00003000[100]
+
+
+Checkpoint_32_BankViewTableUndo=00000000[100]00001000[100]00002000[100]00003000[100]
+
+
+Checkpoint_8_TileCollisionProperties=00[400]
+
+
+Checkpoint_8_TileCollisionPropertiesUndo=00[400]
+
+
+Checkpoint_PropertyConditions=[20]
+
+
+Checkpoint_PropertyConditionsUndo=[20]
+
+
+Checkpoint_TilePropConditionType=00[7]02
+
+
+Checkpoint_TilePropConditionTypeUndo=00[7]02
+
+
+Checkpoint_MetatileSet_2x2_id=00[400]
+
+
+Checkpoint_MetatileSet_2x2_idUndo=00[400]
+
+
+Checkpoint_MetatileSet_2x2_pal=00[400]
+
+
+Checkpoint_MetatileSet_2x2_palUndo=00[400]
+
+
+Checkpoint_MetatileSet_2x2_props=00[400]
+
+
+Checkpoint_MetatileSet_2x2_propsUndo=00[400]
+
+
+Checkpoint_MetatileSet_4x4_id=00[1000]
+
+
+Checkpoint_MetatileSet_4x4_idUndo=00[1000]
+
+
+Checkpoint_MetatileSet_4x4_pal=00[1000]
+
+
+Checkpoint_MetatileSet_4x4_palUndo=00[1000]
+
+
+Checkpoint_MetatileSet_4x4_props=00[1000]
+
+
+Checkpoint_MetatileSet_4x4_propsUndo=00[1000]
+
+
+Checkpoint_MetatileSet_8x8_id=00[2000]
+
+
+Checkpoint_MetatileSet_8x8_idUndo=00[2000]
+
+
+Checkpoint_MetatileSet_8x8_pal=00[2000]
+
+
+Checkpoint_MetatileSet_8x8_palUndo=00[2000]
+
+
+Checkpoint_MetatileSet_8x8_props=00[2000]
+
+
+Checkpoint_MetatileSet_8x8_propsUndo=00[2000]
+
+
+Checkpoint_MetatileSetLabels_2x2=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+Checkpoint_MetatileSetLabels_2x2Undo=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+Checkpoint_MetatileSetLabels_4x4=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+Checkpoint_MetatileSetLabels_4x4Undo=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+Checkpoint_MetatileSetLabels_8x8=Unlabeled,Unlabeled
+Checkpoint_MetatileSetLabels_8x8Undo=Unlabeled,Unlabeled
+
+Checkpoint_CHRBankLabels=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+Checkpoint_CHRBankLabelsUndo=Unlabeled,Unlabeled,Unlabeled,Unlabeled
+
+
+Checkpoint_32_NTSC_MsprDuration=00000006[100]
+
+
+Checkpoint_32_NTSC_MsprDurationUndo=00000000[100]
+
+
+Checkpoint_32_PAL_MsprDuration=00000005[100]
+
+
+Checkpoint_32_PAL_MsprDurationUndo=00000000[100]
+
+
+Checkpoint_MsprDirectTagStart=[100]
+
+
+Checkpoint_MsprDirectTagStartUndo=[100]
+
+
+Checkpoint_MsprDirectTagLoop=[100]
+
+
+Checkpoint_MsprDirectTagLoopUndo=[100]
+
+
+Checkpoint_MsprDirectTagCall=[100]
+
+
+Checkpoint_MsprDirectTagCallUndo=[100]
+
+
+Checkpoint_MsprDirectTagCall2=[100]
+
+
+Checkpoint_MsprDirectTagCall2Undo=[100]
+
+
+Checkpoint_MsprDirectTagRevert=[100]
+
+
+Checkpoint_MsprDirectTagRevertUndo=[100]
+
+
+Checkpoint_MsprDirectTagSeconds=[100]
+
+
+Checkpoint_MsprDirectTagSecondsUndo=[100]
+
+
+Checkpoint_MsprDirectTagHalfSeconds=[100]
+
+
+Checkpoint_MsprDirectTagHalfSecondsUndo=[100]
+
+=========================================================
+Current settings switch tiles
+=========================================================
+
+
+
+Metadata:
+---------------------------------------------------------
+Switch tiles enabled=0
+Current preset ID=0
+
+GUI behaviour:
+---------------------------------------------------------
+Use paired mode if possible=0
+Affect backgrounds=1
+Affect sprites=1
+
+Nonpaired mode start set behaviour:
+---------------------------------------------------------
+Nonpaired, Use set of 1st checked switch tile=1
+Nonpaired, Use active set=0
+Nonpaired, Use fixed set=0
+Nonpaired, fixed set ID=0
+
+Paired mode start set behaviour:
+---------------------------------------------------------
+Paired, Use set of 1st checked switch tile=1
+
+Switch tile IDs:
+---------------------------------------------------------
+Switch tile 1 ID=254
+Switch tile 2 ID=253
+Switch tile 3 ID=252
+Switch tile 4 ID=251
+
+Switch tile targets:
+---------------------------------------------------------
+Switch tile 1 target=0
+Switch tile 2 target=4096
+Switch tile 3 target=8192
+Switch tile 4 target=12288
+
+Switch tile checkboxes:
+---------------------------------------------------------
+Switch tile 1 checkbox=1
+Switch tile 2 checkbox=1
+Switch tile 3 checkbox=1
+Switch tile 4 checkbox=1
diff --git a/config/nrom.cfg b/config/nrom.cfg
new file mode 100644
index 0000000..41a1f2a
--- /dev/null
+++ b/config/nrom.cfg
@@ -0,0 +1,24 @@
+##
+# Same as the default NROM configuration provided by cc65, but with C stuff
+# stripped away (e.g. namely, there are no more segments like 'STARTUP').
+
+MEMORY {
+ # iNES header
+ HEADER: file = %O, start = $0000, size = $0010, fill = yes;
+
+ # Fixed ROM.
+ ROM0: file = %O, start = $8000, size = $7FFA, fill = yes, define = yes;
+
+ # Hardware Vectors.
+ ROMV: file = %O, start = $FFFA, size = $0006, fill = yes;
+
+ # 1 8k CHR Bank
+ ROM2: file = %O, start = $0000, size = $2000, fill = yes;
+}
+
+SEGMENTS {
+ HEADER: load = HEADER, type = ro;
+ CODE: load = ROM0, type = ro, define = yes;
+ VECTORS: load = ROMV, type = rw;
+ CHARS: load = ROM2, type = rw;
+}
diff --git a/include/apu.s b/include/apu.s
new file mode 100644
index 0000000..65d9876
--- /dev/null
+++ b/include/apu.s
@@ -0,0 +1,4 @@
+.scope APU
+ DMC = $4010
+ FRAME_COUNTER = $4017
+.endscope
diff --git a/include/globals.s b/include/globals.s
new file mode 100644
index 0000000..d22b217
--- /dev/null
+++ b/include/globals.s
@@ -0,0 +1,34 @@
+;; Global variables used throughout the code base.
+.scope Globals
+ ;;;
+ ;; Argument values as defined in https://github.com/mssola/style.nes. Note
+ ;; that these variables can also be used as temporary variables.
+ zp_arg0 = $00
+ zp_arg1 = $01
+ zp_arg2 = $02
+ zp_arg3 = $03
+ zp_arg4 = $04
+
+ ;;;
+ ;; Random values that can be used inside of functions for temporary values
+ ;; so `zp_argX` variables are not overwritten as often.
+ zp_tmp0 = $05
+ zp_tmp1 = $06
+ zp_tmp2 = $07
+ zp_tmp3 = $08
+
+ ;;;
+ ;; Reserve a byte of memory for preserving indices on memory. This is needed
+ ;; whenever the `x` and `y` registers might not be reliable because of
+ ;; underlying `jsr` calls that might tamper with their values. Sometimes
+ ;; saving the value in memory is enough instead of playing with the stack.
+ zp_idx = $09
+
+ ;; Flags that manage the state of the game.
+ ;;
+ ;; | Bit | Short name | Meaning when set |
+ ;; |-----+------------+-------------------------------------------------------------|
+ ;; | 7 | render | Game logic is over, block main code until NMI code is over. |
+ ;; | 6-0 | - | Unused |
+ zp_flags = $20
+.endscope
diff --git a/include/oam.s b/include/oam.s
new file mode 100644
index 0000000..22935b2
--- /dev/null
+++ b/include/oam.s
@@ -0,0 +1,11 @@
+.scope OAM
+ ADDRESS = $2003
+ DMA = $4014
+.endscope
+
+.macro OAM_WRITE_SPRITES
+ lda #$00
+ sta OAM::ADDR
+ lda #$02
+ sta OAM::DMA
+.endmacro
diff --git a/include/ppu.s b/include/ppu.s
new file mode 100644
index 0000000..fa0df19
--- /dev/null
+++ b/include/ppu.s
@@ -0,0 +1,8 @@
+.scope PPU
+ CONTROL = $2000
+ MASK = $2001
+ STATUS = $2002
+ SCROLL = $2005
+ ADDRESS = $2006
+ DATA = $2007
+.endscope
diff --git a/src/jetpac.s b/src/jetpac.s
new file mode 100644
index 0000000..2f273a3
--- /dev/null
+++ b/src/jetpac.s
@@ -0,0 +1,86 @@
+.segment "HEADER"
+ .byte 'N', 'E', 'S', $1A
+ .byte $02, $01
+ .res $0A, $00
+
+.segment "CODE"
+
+.include "../include/apu.s"
+.include "../include/oam.s"
+.include "../include/ppu.s"
+.include "../include/globals.s"
+.include "vectors.s"
+
+.proc main
+ jsr init_palettes
+ jsr init_nametables
+
+;;; TODO
+ cli
+ lda #%10110000
+ sta $2000
+ lda #%00011110
+ sta $2001
+
+@main_game_loop:
+ ;;;
+ ;; TODO
+ ;;;
+
+ lda #%10000000
+ ora Globals::zp_flags
+ sta Globals::zp_flags
+@wait_for_render:
+ bit Globals::zp_flags
+ bmi @wait_for_render
+
+ ;; Rendering is done, we can perform another iteration of the loop!
+ jmp @main_game_loop
+.endproc
+
+;; Copies all the palettes for our game into the proper PPU address.
+.proc init_palettes
+ lda #$3F
+ sta PPU::ADDRESS
+ lda #$00
+ sta PPU::ADDRESS
+
+ ldx #0
+@load_palettes_loop:
+ lda palettes, x
+ sta PPU::DATA
+ inx
+ cpx #$20
+ bne @load_palettes_loop
+ rts
+palettes:
+ ;; Background
+ ;; 0: score
+ .byte $0F, $30, $2C, $28
+ ;; 1: floating platforms
+ .byte $0F, $2C, $30, $2A
+ ;; 2: ground
+ .byte $0F, $28, $14, $28
+ ;; 3: ship
+ .byte $0F, $16, $30, $00
+
+ ;; TODO: fuel tank needs color $24
+ ;; Foreground
+ ;; 0: player & ship
+ .byte $0F, $16, $10, $30
+ ;; 1: enemy 1 & bonuses
+ .byte $0F, $16, $2C, $2A
+ ;; 2: enemy 2, fuel & bonuses
+ .byte $0F, $16, $14, $28
+ ;; 3: SUSE easter egg
+ .byte $0F, $16, $00, $2B
+.endproc
+
+.proc init_nametables
+ ;; TODO
+ rts
+.endproc
+
+
+.segment "CHARS"
+ .incbin "../assets/jetpac.chr"
diff --git a/src/vectors.s b/src/vectors.s
new file mode 100644
index 0000000..2edc6a6
--- /dev/null
+++ b/src/vectors.s
@@ -0,0 +1,109 @@
+.segment "VECTORS"
+ .addr nmi, reset, irq
+
+.segment "CODE"
+
+;; Pretty standard reset function, nothing crazy.
+.proc reset
+ sei
+ cld
+
+ ldx #$40
+ stx APU::FRAME_COUNTER
+
+ ldx #$FF
+ txs
+
+ inx
+ stx PPU::CONTROL
+ stx PPU::MASK
+ stx APU::DMC
+
+@vblankwait1:
+ bit PPU::STATUS
+ bpl @vblankwait1
+
+ ldx #0
+ lda #0
+@ram_reset_loop:
+ sta $000, x
+ sta $100, x
+ sta $300, x
+ sta $400, x
+ sta $500, x
+ sta $600, x
+ sta $700, x
+ inx
+ bne @ram_reset_loop
+
+ lda #$EF
+@sprite_reset_loop:
+ sta $200, x
+ inx
+ bne @sprite_reset_loop
+
+ lda #$00
+ sta OAM::ADDRESS
+ lda #$02
+ sta OAM::DMA
+
+@vblankwait2:
+ bit PPU::STATUS
+ bpl @vblankwait2
+
+ lda #$3F
+ sta PPU::ADDRESS
+ lda #$00
+ sta PPU::ADDRESS
+
+ lda #$0F
+ ldx #$20
+@palettes_reset_loop:
+ sta PPU::DATA
+ dex
+ bne @palettes_reset_loop
+
+ jmp main
+.endproc
+
+.proc nmi
+ ;; Should we skip it?
+ bit Globals::zp_flags
+ bpl @end
+
+ ;; Save registers.
+ pha
+ txa
+ pha
+ tya
+ pha
+
+ lda #$00
+ sta OAM::ADDRESS
+ lda #$02
+ sta OAM::DMA
+
+ bit PPU::STATUS
+ lda #$00
+ sta PPU::SCROLL
+ sta PPU::SCROLL
+
+ lda #%01111111
+ and Globals::zp_flags
+ sta Globals::zp_flags
+
+ ;; Restore registers.
+ pla
+ tay
+ pla
+ tax
+ pla
+
+@end:
+ rti
+.endproc
+
+;; Unused.
+.proc irq
+ rti
+.endproc