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97 lines
2.8 KiB
Plaintext
97 lines
2.8 KiB
Plaintext
<!doctype linuxdoc system>
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<article>
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<title>Picocomputer 6502 - specific information for cc65
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<author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">
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<abstract>
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An overview over the Picocomputer 6502 and its interfaces to the cc65 C
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compiler.
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</abstract>
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<!-- Table of contents -->
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<toc>
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<!-- Begin the document -->
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<sect>Overview<p>
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The Picocomputer 6502 is a modern W65C02S computer with a custom operating
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system designed to be POSIX-like. The reference design includes a W65C02S,
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W65C22S, RP6502-RIA, and optionally a RP6502-VGA. Peripheral devices like
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keyboards, mice, and flash storage are connected by USB to the RP6502-RIA.
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Audio is generated by the RP6502-RIA. Video is generated by the RP6502-VGA.
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<sect>Binary format<p>
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The standard binary output format generated by the linker for the RP6502 target
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is a plain machine language program without any prefix or postfix.
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The RP6502 Integrated Development Environment, based on Visual Studio Code,
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will convert the cc65 binary output into RP6502 ROM files that can be loaded
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directly from the RP6502 monitor or installed on the RIA to be loaded at boot.
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<sect>Memory layout<p>
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<descrip>
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<tag/Stack/
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The C run-time stack is located at $FEFF, and grows downward.
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<tag/Heap/
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The C heap is located at the end of the program, and grows toward the C
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run-time stack.
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<tag/RAM/
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RAM is located at $0000 - $FEFF. Default binaries load and
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start at $0200.
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<tag/ROM/
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The RP6502 is designed with no ROM in the 6502 address space.
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<tag/VIA/
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A Versatile Interface Adapter (6522) is 16 registers located
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at $FFD0.
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<tag/RIA/
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The RP6502 Interface Adapter is 32 registers located at $FFE0.
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<tag/User/
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User I/O expansion is from $FF00 to $FFCF.
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</descrip><p>
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<sect>Platform-specific header files<p>
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Programs containing RP6502-specific code may use the <tt/rp6502.h/ or
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<tt/rp6502.inc/ include files.
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<sect>License<p>
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This software is provided "as-is", without any expressed or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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<enum>
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<item> The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated, but is not required.
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<item> Altered source versions must be plainly marked as such, and must not
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be misrepresented as being the original software.
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<item> This notice may not be removed or altered from any source
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distribution.
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</enum>
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</article>
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