This memory map is a guide to the way a commodore 128 in. Introduced in january 1985 at the ces in las vegas, it appeared three years after its predecessor, the bestselling commodore 64. The commodore 128, also known as the c128, c128, c 128, is the last 8bit home computer that was commercially released by commodore business machines cbm. How was a line of commodore 64 basic code stored in its memory. The address space may look different from the view of other chips such as the vic. C64 cpm and c128 cpm both suffer a lack of software. Feb 15, 20 commodore 64 pitfall ii assembly language hack. Hey guys, whats up, as some of you know, i love coding 8bit games in c. This book is a map of all of those memory locations, but its more than just a list of addresses. The memory map of the commodore 64 mode and its basic 2. Memory management in basic c64 os an os with modern. This is the current version of the memory map navigator software, for use on windows 7 or later.
Gettyp 1154 4436 replace shape mode strptr 1155 4437 string posn counter oldbyt 1156 4438 old bit map byte newbyt 1157 4439 new string or bit map byte 1158 4440. Each ram expansion changes the ordering andor placement of basic and the screen such that most software is compatible with only exactly one memory layout. Zero page for machine code programs commodore 64 c64 forum. The memory map directs you in finding address vectors for routines and entry points and provi des information about the general layout of the computer. As features are added andor modified it might be necessary to change these assignments. The master memory map for the commodore 64 internet archive. Memorymap gps mapping apps for pc, iphone, ipad, android. Id need to check my sources before giving a confident answer, but this i can tell you offhand with certainty.
Furthermore, the z80 processor is underclocked to be compatible with the c64 s memory bus, so performance is poor compared to other cpm implementations. You can write assembly code and test this with the vice emulator. Personally, i think commodore 128 bedienungshandbuch contains much more detailed information than commodore 128 system guide. C64 studio is an assembly development environment which is dependent on vice. Why is programming the c64 so hard commodore 64 c64 forum. These are the zeropage memory locations for the rs232. Jun 19, 2015 the first 256 bytes of memory in the c64 is referred to as a. Jun 10, 2016 i introduce the c64 memory map by way of tracing the circuits used to activate the vicii for reads and writes. Besides faster fetching and storing fromto these addresses, the 65xx cpus offer the indirectindexed addressing mode which only work on zeropage addresses. Also, some reference of the kernal routines and a memory map of the c64 will be helpful. With the cpm cartridge plugged into your c64 and cpm running what did you get. Windows pc software downloads memory map navigator v6. The goal of project 64 is to preserve commodore 64 related documents in electronic text format that might otherwise cease to exist with the rapid.
Commodore 64 pitfall ii assembly language hack youtube. Use the digital map store button to explore additional maps and charts. I know like half a dozen assembly commands, and still have a lot to learn in that area an. You can find the full set of c64 zero page locations and the purposes in the commodore 64 memory map section starting on page 310 of the comodore 64 programmers reference guide. This is where the kernal will start executing our bootloader code, so well use the monitor again to disassemble that code. Its an easy typo to grab the contents of memory location zero instead of the constant zero, it can be difficult to spot so keep an eye out for it. May 16, 2016 the best is to replace all chips but there are quite a few tips on how to detect which chip might be broken. The petcbms have limited zero page zp memory available. Refer to the memory map whenever you need directions throughout the memory of your commodore 128. Memory 0285 645 serial bus timeout flag 0286 646 current color code 0287 647 color under cursor 0288 648 screen memory page. Frekzp 00fb00fe 251 free zero page space for user programs. A memory map tells you exactly how memory is laid out internally in both ram and rom. The chip for bit 3 might be u10 dont have a schematic here in the moment but if lemon64 says so it should be correct. Low memory zero page or base page is the series of memory addresses at the very beginning of a computers address space.
Memory map gps mapping apps for pc, iphone, ipad, android. Memory map free gps mapping software for pc, iphone, ipad. The c64 doesnt really have enough registers that it can afford to dedicate any of them to a particular variable, but cc65 does try to take advantage of the c register keyword. The size of a page depends on the context, and the significance of zero page memory versus higher addressed memory is highly dependent on machine architecture. A address of zero page register holding start address of memory area to save. This chapter provides the memory maps for both c128 and c64 modes. Memory activity of a commodore 64 while running a game oc. The random access memory ram, readonly memory rom, and interface hardware chips in your commodore 128 are like postal stations with hundreds of thousands of mailboxes, each of which can hold a single character, or byte of information. Commodore 128 bedienungshandbuch is not a direct translation of commodore 128 system guide from english to german. The following article shows a short overview of the c64 memory map pages and memory adresses as seen by its cpu. I manually laid out the areas with special significance to the c64.
Register is a hint that the compiler should store the variable in a reserved chunk of space in page zero of the c64s memory map. Just wondering if you could basically use almost all of the c64 ram in my code besides the first two bytes and the last two which would be used for irq pointer since the kernal is swapped out. The transactor fall 83 converted to digital by modore. These locations are most often the area used by games to hold temporary data and weall discuss that in the a. Why does the commodore 64 leave these pointers in zeropage. But seriously, its hard because programming a computer to perform any complex task is hard when you dont get anything for free. Yes, the instead of a indicates that the ram chip for bit 3 is causing the issue because 0x28 and 0x20 in petscii coding. The systems software allows compatability with any rs232 device prin ter, modem, etc.
Besides the obvious first two bytes of memory, can you use all of zero page for machine code programs that swap out basic and kernal. Memory locations that have been reassigned should not be regarded as permanently set. Full text of the master memory map for the commodore 64. The project 64 etext of several commodore 64 memory maps. These locations are most often the area used by games to hold temporary data and well discuss that in the training section.
It is the software which calls the kernal that needs to decide where to put. But mapping the commodore 64 is a memory amp that goes much further. If you see random characters on the screen you might determine which bit isnt okay and which chip is responsible for it. Memory maps should usually specify which programs use this memory.
To accomplish this, emulator will create multiple memory maps are preconfigured for each possible configuration. What you want is the programmers reference guide that and a copy of compute. The purpose of this page would be to document the exact. Memory map free gps mapping software for pc, iphone.