252 lines
7.0 KiB
Plaintext
252 lines
7.0 KiB
Plaintext
************************************************
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* *
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* CZ80 (Z80 CPU emulator) version 0.91 *
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* Compiled with Dev-C++ *
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* Copyright 2004-2005 Stéphane Dallongeville *
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* *
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************************************************
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CZ80 is a Z80 CPU emulator, priorities were given to :
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- code size
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- speed
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- accuracy
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- portablity
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It supports almost all undocumented opcodes and flags.
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The emulator can be freely distribued and used for any non commercial
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project as long you don't forget to credit me somewhere :)
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If you want some support about the CZ80, you can contact me on
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the Gens forum (http://gens.consolemul.com then go to the forum).
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You should find the following files in the emulation pack :
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- cz80.h -> header file (prototypes, declarations...)
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- cz80.c -> contains emulation core itself
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- cz80.inc -> contains most used macros
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- cz80jmp.inc -> Jump table definition when Jump Table used
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- cz80exec.inc -> contains the major Cz80_Exec(...) function
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- cz80_op.inc -> contains code for simple Z80 opcodes emulation
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- cz80_opCB.inc -> contains code for CB prefixed Z80 opcodes emulation
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- cz80_opED.inc -> contains code for ED prefixed Z80 opcodes emulation
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- cz80_opXY.inc -> contains code for DD/FD prefixed Z80 opcodes emulation
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- cz80_opXYCB.inc -> contains code for DD/FD + CB prefixed Z80 opcodes emulation
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- readme.txt -> the current file you're reading ;)
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* How compile the emulator ?
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****************************
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The emulator has been written with Dev-CPP 4.9.X.X
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You will maybe need to modify the u8, u16, u32, s8, s16, s32 and FASTCALL
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definitions (cz80.h) according to your C compiler and the target system.
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Then compile the cz80.c file, you should obtain a cz80.o (or cz80.obj) file...
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at this moment, you're ready to use the emulator just by linking the file in your project :)
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* How to use the emulator ?
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***************************
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1) Include the header file in your source :
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------------------------------------------
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#include "cz80.h"
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2) Init the CZ80 core :
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-----------------------
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If you want to use the internal CZ80 context offered :
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Cz80_Init(&CZ80);
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but you can also define your own CZ80 context :
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cz80_struc My_Z80;
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....
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Cz80_Init(&My_Z80);
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You'll can emulate as many Z80 CPU as you want by defining severals CZ80 contexts.
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An arbitrary pointer can also be stored in the CZ80 context.
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This pointer is passed to each I/O callback:
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Cz80_Set_Ctx(&CZ80, &user_context);
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3) Set up your fetch region (where the Z80 will run code from) :
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----------------------------------------------------------------
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Cz80_Set_Fetch(&CZ80, 0x0000, 0x7FFF, (u32) your_ROM);
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Cz80_Set_Fetch(&CZ80, 0xA000, 0xFFFF, (u32) your_RAM);
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...
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4) Set up your memory (where the Z80 will read and write data) :
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----------------------------------------------------------------
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Cz80_Set_ReadB(&CZ80, your_z80readbyte_function);
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Cz80_Set_WriteB(&CZ80, your_z80readbyte_function);
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You can improve CZ80 performance by using WORD read/write function.
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For that, you need to enable the 'CZ80_USE_WORD_HANDLER' define in cz80.h file.
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In this case, you'll need to add that :
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#if CZ80_USE_WORD_HANDLER
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Cz80_Set_ReadW(&CZ80, your_z80readword_function);
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Cz80_Set_WriteW(&CZ80, your_z80readword_function);
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#endif
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Your read function need to be of CZ80_READ type :
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typedef u32 FASTCALL CZ80_READ(u32 adr);
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Your write function need to be of CZ80_WRITE type :
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typedef void FASTCALL CZ80_WRITE(u32 adr, u32 data);
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5) Set Up your port (where the Z80 will read and write IO data) :
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-----------------------------------------------------------------
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Cz80_Set_INPort(&CZ80, your_z80readport_function);
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Cz80_Set_OUTPort(&CZ80, your_z80writport_function);
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Your readPort function need to be of CZ80_READ type :
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typedef u32 FASTCALL CZ80_READ(u32 adr);
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Your writePort function need to be of CZ80_WRITE type :
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typedef void FASTCALL CZ80_WRITE(u32 adr, u32 data);
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6) Set Up your interrupt callback function :
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--------------------------------------------
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Cz80_Set_IRQ_Callback(&CZ80, your_z80irqcallback_function);
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Your IRQ callback function need to be of CZ80_INT_CALLBACK type :
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typedef s32 FASTCALL CZ80_INT_CALLBACK(s32 param);
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If you don't understand what i am talking about here, just ignore...
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it's not needed in almost case.
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6) Set Up your RETI callback function :
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---------------------------------------
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Cz80_Set_RETI_Callback(&CZ80, your_z80reticallback_function);
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Your RETI callback function need to be of CZ80_RETI_CALLBACKtype :
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typedef void FASTCALL CZ80_RETI_CALLBACK();
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Again, if you don't understand what i am talking about here, ignore...
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7) Reset the CZ80 core before fisrt use :
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-----------------------------------------
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Cz80_Reset(&CZ80);
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8) Do some cycles :
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-------------------
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Then it's time to really do some work, if you want to execute 1000 cycles, just do :
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cycles_done = Cz80_Exec(&CZ80, 1000);
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Cz80_Exec function return the number of cycles actually done.
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Since each instruction take more than 1 cycle, Cz80_Exec will execute a bit more than
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you requested, for instance here, it can return 1008 cycles instead of 1000.
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In this case, adjust the number of cycle to do like that :
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cycles_by_frame = 4800;
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extra_cycles = 0;
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while (true)
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{
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...
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extra_cycles = CZ80_Exec(&CZ80, cycles_by_frame - extra_cycles) - cycles_by_frame;
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...
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}
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If Cz80_Exec returns a negatif value, an error occured.
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9) Do an interrupt request :
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----------------------------
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Cz80_Set_IRQ(&CZ80, 0);
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or for a NMI :
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Cz80_Set_NMI(&CZ80);
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10) Cancel an interrupt request :
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---------------------------------
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Cz80_Clear_IRQ(&CZ80);
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or for a NMI :
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Cz80_Clear_NMI(&CZ80);
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* Switchs
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*********
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There are severals switchs in the cz80.h file which permit you to configure
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CZ80 depending your needs.
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- CZ80_FETCH_BITS (default = 4)
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This defines the number of bits to select fetch region.
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This value must be 4 <= X <= 12
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Greater value offers permit to have more fetch region.
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In almost case, 4 is enough, but if you have fetch region smaller than 0x1000 bytes,
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increase this value.
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- CZ80_LITTLE_ENDIAN
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Define the endianess of the target platform.
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x86 CPU use Little Endian.
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- CZ80_USE_JUMPTABLE
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Set it to 1 to use Jump table instead of big case statement.
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This can bring some small speed improvemen.
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Be careful, some compiler doesn't support (computed label) so it's
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saffer to not use it.
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- CZ80_SIZE_OPT
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Add some extras optimisation for the code size versus speed.
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Minor changes anyway...
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- CZ80_USE_WORD_HANDLER
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See the "Set Up Memory" section for more détail.
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- CZ80_EXACT
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Enable accurate emulation of extended undocumented opcode and flags.
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minor speed decrease when activated.
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Even without that flag, CZ80 is already uite accurate, keep it
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disable unless you need it or if speed isn't important for you.
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- CZ80_DEBUG
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Used by me, keep it disable :p
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* History
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*********
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Version 0.90 :
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--------------
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* Initial release for debugging purpose ^^
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