README.md

CPU-J65EL02

A C# implementation of the 65el02 CPU.

Dependences for build 🔥

1. NET Core 3.0

Details

• cpu - a cpu impl project
• bootloader - asm code for this cpu
• dasm-cli - nodejs cli applicaion for compile 6502 dasm
• screen - electron application screen emulator

Devices info

- Memory:
    Address: at 0x0000 to 0x***** (not more that 0x40000) 
- Acia6551:
    Address: at 0x8800 to 0x8803
    Registers:
        Data   (DATA_REG) = 0x0 readonly
        Status (STAT_REG) = 0x1 readonly
        Command(CMND_REG) = 0x2 readonly
        Control(CTRL_REG) = 0x3 readonly
    BaudRate: from 0 to 19200
- Acia6850:
    Address: at 0x8800 to 0x8802
    Registers:
        Status  (STAT_REG) = 0x0 readonly
        Command (CTRL_REG) = 0x0 write-only
        ReadRX  (RX_REG)   = 0x1 readonly
        ReadText(TX_REG)   = 0x1 write-only
 - CRTC:
    Address: at 0x9000 to 0x9002
    Registers:
        Select(REG_SELECT) = 0x0 write-olny
        Write (REG_RW)     = 0x1 out and in
 - Bus:
    Address: at 0xFFFFFFFF to 0xFFFFFFFF (no fixed address for the classic-bus)
    Capacity: 0x10 (default)
 - RedBus:
    Address: at 0xFFFFFFFF to 0xFFFFFFFF (no fixed address for the redbus)
    Peripheral:
      Capacity: 0x100 (hardcode)
 - Wireless Display:
    Address: at 0x9500 to 0x9506
    Registers:
        Init        (REGINIT) = 0x0 write-only
        Connect     (REGCON)  = 0x1 write-olny
        WriteChar   (REGWR)   = 0x2 write-olny
        Status      (REGST)   = 0x2 readonly
        PhysPort    (PHPRT)   = 0x3 readonly

Support Instructions

- adc (at 0x69 in Execute)
- sbc (at 0xE9 in Execute)
- cmp (at 0xC0, 0xC4, 0xCC, 0xC9, 0xE0, 0xE4, 0xEC in Execute)
- ror (at 0x6A, 0x66, 0x6E, 0x76, 0x7E in Execute)
- mul (at 0x0F, 0x1F, 0x2F, 0x3F in Execute)
- div (at 0x4F, 0x5F, 0x6F, 0x7F in Execute)
- asl (at 0x0A, 0x06, 0x0E, 0x16, 0x1E in Execute)
- lsr (at 0x4A, 0x46, 0x4E, 0x56, 0x5E in Execute)
- rol (at 0x2A, 0x26, 0x2E, 0x36, 0x3E in Execute)

- xadr   (at 0x7 in cycle-address)
- yadr   (at 0x7 in cycle-address)
- zpxadr (at 0x5 in cycle-address)
- zpyadr (at 0x5 in cycle-address)

Sizes of instructions

1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 2,   // 0x00-0x0f
2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 2,   // 0x10-0x1f
3, 2, 1, 2, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0x20-0x2f
2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0x30-0x3f
1, 2, 1, 2, 3, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 2,   // 0x40-0x4f
2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 1, 1, 1, 3, 3, 2,   // 0x50-0x5f
1, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0x60-0x6f
2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0x70-0x7f
2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 1,   // 0x80-0x8f
2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 1,   // 0x90-0x9f
2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 1,   // 0xa0-0xaf
2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 1,   // 0xb0-0xbf
2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 1,   // 0xc0-0xcf
2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 1, 1, 1, 3, 3, 1,   // 0xd0-0xdf
2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 2,   // 0xe0-0xef
2, 2, 2, 2, 3, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 0    // 0xf0-0xff

Addressing modes

  ACC, AIX, ABS, ABX, ABY,
  ASP, ABR, IMM, IMP, IND,
  XIN, INY, ISY, IRY, REL,
  ZPG, ZPR, ZPX, ZPY, ZPI,
  NUL

WSoD (White Screen of Dead)

WSoD displays information about the last write\read memory, error information, as well as cpu-state, cpu-flags and devices that are currently in the bus.