PC-G815 Compatible Z80 Emulator

SHARP STYLE BOOTING 0.00x

Machine Monitor

BOOTING

Main Registers

Shadow Registers

Flags (Main F)

0x00

Address Bus

0x0000

Data Bus

0x00

CPU Pins (H/L)

Input Log

Key Matrix Map

BASIC Editor

Idle

Editor focus: keyboard input types into this editor. Outside editor focus: keys control the emulator. RUN executes: NEW -> program lines -> RUN.

Language reference: basic-language-spec.md

Z80 Assembler

Idle

Assemble generates machine code with ORG/ENTRY. Run loads assembled bytes into RAM and starts execution at ENTRY.

Language reference: assembly-language-spec.md / z80-assembly-mnemonics.md / pc-g815-io-port-spec.md

ORG 0x0200
ENTRY START

START:
  LD A,0x40
  OUT (0x58),A
  LD A,0x80
  OUT (0x58),A
  LD HL,PROMPT_IN
  CALL PRINT_STR

LD HL,BUFFER
  XOR A
  LD (LEN),A

READ_LOOP:
  PUSH HL
  CALL READ_KEY
  POP HL
  CP 0x0D
  JR Z,INPUT_DONE
  CP 0x08
  JR Z,HANDLE_BS

LD C,A
  LD A,(LEN)
  CP 24
  JR NC,READ_LOOP
  LD A,C
  LD (HL),A
  INC HL
  LD A,(LEN)
  INC A
  LD (LEN),A
  LD A,C
  OUT (0x5A),A
  JR READ_LOOP

HANDLE_BS:
  LD A,(LEN)
  OR A
  JR Z,READ_LOOP
  DEC HL
  DEC A
  LD (LEN),A
  LD A,0x08
  OUT (0x5A),A
  JR READ_LOOP

INPUT_DONE:
  LD A,0x0D
  OUT (0x5A),A
  LD A,0x0A
  OUT (0x5A),A
  LD HL,PROMPT_OUT
  CALL PRINT_STR

LD A,(LEN)
  OR A
  JR Z,PRINT_EOL
  LD B,A
  LD HL,BUFFER
  LD E,A
  LD D,0
  ADD HL,DE
  DEC HL

REV_LOOP:
  LD A,(HL)
  OUT (0x5A),A
  DEC HL
  DJNZ REV_LOOP

PRINT_EOL:
  LD A,0x0D
  OUT (0x5A),A
  LD A,0x0A
  OUT (0x5A),A

DONE:
  RET

PRINT_STR:
  LD A,(HL)
  OR A
  RET Z
  OUT (0x5A),A
  INC HL
  JR PRINT_STR

READ_KEY:
WAIT_CLEAR:
  CALL SCAN_KEY
  JR NZ,WAIT_CLEAR
WAIT_PRESS:
  CALL SCAN_KEY
  JR Z,WAIT_PRESS
  RET

SCAN_KEY:
  LD A,0x80
  OUT (0x11),A
  IN A,(0x10)
  LD B,0
  BIT 0,A
  JR Z,SHIFT_ON
  BIT 1,A
  JR NZ,SHIFT_DONE
SHIFT_ON:
  LD B,1
SHIFT_DONE:
  LD C,0x01
  LD D,0x00

SCAN_ROW:
  LD A,C
  OUT (0x11),A
  IN A,(0x10)
  CPL
  AND 0xFF
  JR NZ,ROW_HIT
  INC D
  SLA C
  JR NZ,SCAN_ROW
  XOR A
  RET

ROW_HIT:
  LD E,0
  BIT 0,A
  JR NZ,COL_FOUND
  INC E
  BIT 1,A
  JR NZ,COL_FOUND
  INC E
  BIT 2,A
  JR NZ,COL_FOUND
  INC E
  BIT 3,A
  JR NZ,COL_FOUND
  INC E
  BIT 4,A
  JR NZ,COL_FOUND
  INC E
  BIT 5,A
  JR NZ,COL_FOUND
  INC E
  BIT 6,A
  JR NZ,COL_FOUND
  INC E
  BIT 7,A
  JR NZ,COL_FOUND
  XOR A
  RET

COL_FOUND:
  LD A,D
  ADD A,A
  ADD A,A
  ADD A,A
  ADD A,E
  LD E,A
  LD D,0
  LD HL,NORMAL_TABLE
  LD A,B
  OR A
  JR Z,TABLE_OK
  LD HL,SHIFT_TABLE
TABLE_OK:
  ADD HL,DE
  LD A,(HL)
  OR A
  RET

PROMPT_IN:
  DB "Input Word: ",0
PROMPT_OUT:
  DB "Reversed: ",0
LEN:
  DB 0
BUFFER:
  DS 24,0

NORMAL_TABLE:
  DB 0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48
  DB 0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,0x50
  DB 0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58
  DB 0x59,0x5A,0x3B,0x27,0x5B,0x5D,0x5C,0x60
  DB 0x09,0x1B,0x08,0x00,0x00,0x00,0x00,0x00
  DB 0x37,0x38,0x39,0x2D,0x3D,0x2C,0x2E,0x2F
  DB 0x00,0x30,0x31,0x32,0x33,0x34,0x35,0x36
  DB 0x00,0x00,0x0D,0x08,0x20,0x00,0x00,0x00

SHIFT_TABLE:
  DB 0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68
  DB 0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,0x70
  DB 0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78
  DB 0x79,0x7A,0x3A,0x22,0x7B,0x7D,0x7C,0x7E
  DB 0x09,0x1B,0x08,0x00,0x00,0x00,0x00,0x00
  DB 0x26,0x2A,0x28,0x5F,0x2B,0x3C,0x3E,0x3F
  DB 0x00,0x29,0x21,0x40,0x23,0x24,0x25,0x5E
  DB 0x00,0x00,0x0D,0x08,0x20,0x00,0x00,0x00