Thank you to the viewers who pointed out the issue at the
end of the stream.
At this point, simple code works, but the conditional
from the joystick input does not seem to work yet.
* also add location header for linker
* also filter errors and directives better
write_multi_color_line(), write_line(): Remove.
VIC_II::SpriteLine<bool multicolor>: A line of sprite bitmap data.
The constructor converts one line of data at a time.
VIC_II::Sprite<bool multicolor>: An array of SpriteLine.
This change does not affect the generated binary code.
In the assembler code generated by clang++-4.0, the binary data
will be formatted in groups of 3 bytes instead of 3*21 bytes.
VIC_II::SPRITE_ALIGNMENT: The MOS 6566/6567/6569 VIC-II expects
sprite data to be aligned at 64 bytes.
VIC_II::SPRITE_STARTING_BANK: Remove.
VIC_II::write_multi_color_pixel(), VIC_II::write_pixel(): Make static.
Write to the specified memory address.
VIC_II::Sprite::Sprite(): Refactored from VIC_II::make_sprite().
VIC_II::enable_sprite(): Take a Sprite reference.
sBall, sBat: Sprite images, declared at global scope.
FIXME: How to ensure that the VIC_II::Sprite addresses do not end up in
the range 0x1000..0x1fff or 0x9000..0x9fff (where the character generator
ROM is overriding RAM)? Any portable alternative to using GCC-style
__attribute__((section("sprites"))) and a linker script?
Note: Declaring the sprite images as static const objects in main()
would cause clang++4.0-svn279916-1 to generate code for initializing them.
So, we will declare the objects in the global scope.
This has been tested on a Commodore 64 with the following steps:
clang++-4.0 -m32 -O3 -std=c++1z -S pong.cpp
x86-to-6502 < pong.s > pong.asm
edit pong.asm to define code start at 0x900 and to adapt the output
invoke some 6502 assembler
SYS2304 to run the output on a Commodore 64
Jason Turner
Robin Degen
Marko Mäkelä