Note: The unused (-) opcodes will lock up the Game Boy CPU when used. Moved, Removed, and Added Opcodes Opcode Z80 GMB The Game Boy operates approximately as fast as a 4 MHz Z80 (8 MHz in CGB double speed mode), with execution time of all instructions having been rounded up to a multiple of 4 cycles. Block commands are gone, but autoincrementing HL accesses are added. IN/OUT (C) are replaced with new LD ($FF00+C) opcodes. That means 16bit memory accesses are mostly missing, 16bit arithmetic functions are heavily cut-down, and some other missing commands. That means no IX- or IY-registers.Īll ED-prefixed instructions are missing. In addition to the removed 8080 instructions, the other exchange instructions have been removed (including total absence of second register set).Īll DD- and FD-prefixed instructions are missing. So have EX (SP),HL (XTHL) and EX DE,HL (XCHG). The sign and parity/overflow flags have been removed, as have the 12 RET, CALL, and JP instructions conditioned on them. Instead, I/O ports are accessed directly by normal LD instructions, or by new LD (FF00+n) opcodes. Unlike the 8080 and Z80, the Game Boy has no dedicated I/O bus and no IN/OUT opcodes. Also, all known Game Boy assemblers use the more obvious Z80-style syntax, rather than the chaotic 8080-style syntax. It is missing a handful of 8080 instructions but does support JR and almost all CB-prefixed instructions. The Game Boy CPU has a bit more in common with an older Intel 8080 CPU than the more powerful Zilog Z80 CPU. Please go to to read Pan Docs or to to contribute.Ĭlick here to go to this section of Pan Docs in the new location: Comparison with 8080 Pan Docs is now officially hosted on gbdev.io as a living document. Z80 CPU User Manual The Z80 CPU contains 208 bits of read/write memory that are available to the program- 16-bit registers. AMD Ryzen Threadripper 3970X 32-Core, 64-Thread Unlocked Desktop Processor 256 3,079003,300. OK Last test :-) 4 years ago TV80-verilog Verilog code moved to TV80-verilog folder 4 years ago Tinybasic Tinybasic added. : Z80 Cpu 1-16 of 50 results for 'z80 cpu' Results DBParts New for 2 Pcs Z80 CPU Microprocessor IC ZILOG DIP-40 Z84C0020PEC Z80CPU Z80-FREE delivery Thu, Apr 27 on 25 of items shipped by Amazon Only 10 left in stock - order soon. The copy of Pan Docs hosted on this wiki is considered deprecated. GitHub - Obijuan/Z80-FPGA: Z80 CPU for OpenFPGAs, with Icestudio Obijuan Z80-FPGA master 1 branch 5 tags Code 177 commits Instruction-exerciser Test 67: stabd.
0 Comments
Leave a Reply. |