Hardware summary

• Z80 @ 3.993600 Mhz
• 64k RAM, 32k ROM + 2K chargen
• VDP: HD46505 (m6845 clone), 48K VRAM total
• Audio: AY-3-8192 on ports 0x18 and 0x19

Classic library support (+multi8)

• Native console output
• Native console input
• ANSI vt100 engine
• Generic console
  • Redefinable font
  • UDG support
  • Paper colour
  • Ink colour
  • Inverse attribute
  • Bold attribute
  • Underline attribute
• Lores graphics
• Hires graphics
• PSG sound
  • ETracker (SAA tracker)
  • PSG Lib (SN76489)
  • Arkos2 Player (AY)
  • WYZ Player (AY)
  • Vortex tracker (AY)
• One bit sound
• Inkey driver
• Hardware joystick
• File I/O
• Interrupts
• RS232

Compilation

zcc +multi8 world.c -create-app

The resulting .cas file can be loaded into an emulator by entering the following commands:

MON
R
GC000

The default compile target is limited to about 10k. To be able to write a larger program we need to switch the machine into all ram mode and then load our program, this can be achieved with the -subtype=64k option:

zcc +multi8 adv_a.c -subtype=64k -create-app -o adv_a

And then load that file as usual.

Generic console modes

• Mode 0 = 40 column text
• Mode 1 = 80 column text
• Mode 2 = 80 column graphics mode

Graphics

Use of the graphics library switches to mode 2 and provides a 640x200 monochrome resolution.

Limitations

Scrolling in mode 2 is particularly slow - we have to move 48kb of data to scroll the display one text line upwards.

Links

• Takeda Emulator
• Technical documentation

Technical notes (not yet implemented)

The im2 vector table is setup at $f000, 8 vectors are available.

A 1Hz interrupt is delivered to the vector at f030 (interrupt 6).

Setup code:

        ld      h,$f7 
        ld      l,$63     
        in      a,($2d)
        and     h
        out     ($2d),a
        ld      a,l
        out     ($2c),a
        ld      de,$f000
        ld      b,8
copy_int_rout:
        push    bc
        ld      hl,int_routine
        ld      bc,8
        ldir
        pop     bc
        djnz    copy_int_rout

        ; f030 is called regularly, set it up as our vector
        ld      a,195
        ld      ($f030),a
        ld      hl,interrupt_dispatch
        ld      ($f031),hl

        EXTERN  im1_vectors
        EXTERN  asm_interrupt_handler

interrupt_dispatch:
        push    af
        push    hl
        ld      hl,im1_vectors
        call    asm_interrupt_handler
        pop     hl
        ld      a,6
ack:
        or      $60
        out     ($2c),a
        pop     af
        ei
        ret

; Interrupt routine that's copied into the vectors
int_routine:
        ei
        reti
        defs      5