pato-z80-home-computer/assembly/bios/main.asm

110 lines
2.0 KiB
NASM
Raw Normal View History

2020-10-27 20:08:07 +01:00
; Pat80 BIOS v0.01
; @author: Daniele Verducci
;
; MEMORY MAP
; ROM is at 0x0000
; RAM is at 0x8000
; SYSTEM VAR SPACE: 0x8000 - 0x8FFF (4kb)
; DRIVERS VAR SPACE: 0x9000 - 0x9FFF (4kb)
; APPLICATION VAR SPACE: 0xA000 - 0xFFFF (24kb)
; I/O MAP
; I/O 0 (0x00 - 0x1F) LCD (uses 0x00 and 0x01)
; I/O 1 (0x20 - 0x3F)
; I/O 2 (0x40 - 0x5F)
; I/O 3 (0x60 - 0x7F)
; I/O 4 (0x80 - 0x9F)
; I/O 5 (0xA0 - 0xBF)
; I/O 6 (0xC0 - 0xDF)
; I/O 7 (0xE0 - 0xFF)
jp Sysinit ; Startup vector: DO NOT MOVE! Must be the first instruction
2020-10-27 20:08:07 +01:00
; SYSTEM CONFIGURATION
IO_0: EQU 0x00
IO_1: EQU 0x20
IO_2: EQU 0x40
IO_3: EQU 0x60
IO_4: EQU 0x80
IO_5: EQU 0xA0
IO_6: EQU 0xC0
IO_7: EQU 0xE0
LCD_INSTR_REG: EQU IO_0
LCD_DATA_REG: EQU IO_0 + 1
SYS_VAR_SPACE: EQU 0x8000
DRV_VAR_SPACE: EQU 0x9000
APP_VAR_SPACE: EQU 0xA000
2020-10-27 20:08:07 +01:00
; CONSTANTS
SYSINIT_GREETING:
DB "Pat80",0 ; null terminated string
2020-10-27 20:08:07 +01:00
LIPSUM:
DB "Lorem ipsum dolor siadipiscing elit. Sedt amet, consectetur dapibus nec nullam.",0
2020-10-27 20:08:07 +01:00
include 'driver_hd44780.asm'
; System initialization
Sysinit:
call Lcd_init
; position to line 2 char 3
;ld b, 1
;ld c, 1
;call Lcd_locate
2020-10-27 20:08:07 +01:00
; write characters to display
;ld bc, SYSINIT_GREETING
;call Lcd_print ; write string to screen
2020-10-27 20:08:07 +01:00
ld bc, LIPSUM
call Lcd_print
2020-10-27 20:08:07 +01:00
;call count
2020-10-27 20:08:07 +01:00
; IO TEST
iotest:
; do not test 0: is lcd
ld a,0x00
out (IO_1),a
ld a,0x00
out (IO_2),a
ld a,0x00
out (IO_3),a
ld a,0x00
out (IO_4),a
ld a,0x00
out (IO_5),a
ld a,0x00
out (IO_6),a
ld a,0x00
out (IO_7),a
call Lcd_cls ; clear screen
halt
2020-10-27 20:08:07 +01:00
; count:
; myVar: EQU APP_VAR_SPACE ; init variable
; ld hl, "A" ; load value into register
; ld (myVar), hl ; copy value into variable
; call count_loop
; count_loop:
; ld bc, myVar
; call lcd_print
; ; increm var
; ld a, (myVar)
; inc a
; ld (myVar), a
; call count_loop