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97 lines
4.1 KiB
Plaintext
97 lines
4.1 KiB
Plaintext
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KEGS Internals
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--------------
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The INTERNALS* files describe the internal structure of KEGS and how
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it works. It is meant to be useful to those who would attempt to
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port KEGS to non-Unix platforms, or just want to know how KEGS works.
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Documentation files:
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--------------------
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INTERNALS.overview: Provides overview of KEGS's file structure
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KEGS SOURCE FILES:
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-----------------
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adb.c: ADB emulation routines. This includes keyboard, mouse, and
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joystick.
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adb.h: Defines for ADB routines.
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clock.c: Clock, BRAM, and some timing routines.
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compile_time.c: Trick file to put the time you compiled in g_compile_time[].
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defc.h: Global defines included by all .c files. Useful trick
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to avoid complex multi-level include problems.
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defs.h: Global defines included by all .s files (assembly language).
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defcomm.h: Global defines included by all files (must be assembly and
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C safe, such as #defines).
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defs_instr.h: C and assembly definitions for various addressing modes
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and for some repeated instructions (like LDA, STA, etc).
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dis.c: Disassembler and debugger interface. The debugger interface
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is similar to the Apple // monitor, but has many
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more commands.
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disas.h: Tables for disassembling 65816 instructions. Not very
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efficient, but it works.
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engine_c.c: C main instruction dispatch loop.
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engine_s.s: Assembly main instruction dispatch loop.
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instable.h: Instruction table. It is C and assembly-safe through
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the make_inst script. make_inst turns instable.h into
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8inst_c and 16inst_c, which are both valid C code.
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iwm.c: IWM routines for 5.25" and 3.5" disks. See INTERNALS.iwm
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iwm.h: IWM defines
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iwm_35_525.h: File for reading and writing a disk byte, which is included
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in iwm.c twice, once for 5.25" and again for 3.5".
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Forcing out compile-time constants this way makes it
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faster.
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moremem.c: Awful name--this file contains the page table change
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routines (fixup_*) and io_read() and io_write() to
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emulate all $C000 I/O accesses.
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op_routs.h: More macros for 65816 emulation.
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protos.h: Prototypes for all C functions. Auto-generated through
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the "cproto" program (not included).
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protos_xdriver.h: Prototypes for functions in xdriver.c.
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scc.c: Serial chip emulation.
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scc_driver.h: Unix-specific socket routines, stubbed out if you're not
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on Linux or HP-UX.
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scc.h: Defines for scc.c.
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sim65816.c: main() is here along with many other housekeeping
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functions, such as events, and interrupts.
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The main loop of KEGS is run_prog().
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size_tab.h: Used by assembly for a jump table (make_size script
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turns it into 8size_s and 16size_s) and by both C and
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assembly to get the size of instructions.
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smartport.c: Smartport emulation, emulates s7dx devices.
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sound.c: Sound emulation. Builds sound samples, but does not
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send sound to output device.
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sound.h: Header file for sound.c.
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sound_driver.c: Sound driver routines. Takes samples generated by sound.c
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and sends them to the correct output device. Supports
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HP Alib, HP /dev/audio, and Linux /dev/dsp currently.
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superhires.h: "macro" routine used by video.c so that I could write
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one generic superhires routine, but then include it
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multiple times to get optimized 320 vs 640 mode routines.
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video.c: Display routines. Builds 8 bit video buffers in a
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device independent way. Functions here know nothing
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about X windows.
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xdriver.c: X windows driver routines. Takes buffers from video.c
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and sends them on to X windows. Get keypresses from
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X and sends them to adb.c.
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Porting Advice:
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--------------
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To a non-unix platform, disabling scc emulation would be a good start.
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Just make sure you get the dummy stub routines in scc_driver.h.
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If you don't have gettimeofday(), clock.c will need to modified with
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whatever timer facilities are available. A high-resolution clock works
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best, but even a low-resolution clock will work.
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Modify sound_driver.c to get it to compile, if necessary. Always run with
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"-audio 0" to turn audio off. No routines in sound_driver.c will get
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called if you run with -audio 0.
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Replace xdriver.c with new routines for whatever platform you are porting to.
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See INTERNALS.xdriver for more information.
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