79 lines
1.5 KiB
NASM
79 lines
1.5 KiB
NASM
jp Sysinit ; Startup vector: DO NOT MOVE! Must be the first instruction
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; Pat80 BIOS v0.01
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; @author: Daniele Verducci
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;
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; MEMORY MAP
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; ROM is at 0x0000
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; RAM is at 0x8000
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; SYSTEM VAR SPACE: 0x8000 - 0x8FFF (4kb)
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; DRIVERS VAR SPACE: 0x9000 - 0x9FFF (4kb)
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; APPLICATION VAR SPACE: 0xA000 - 0xFFFF (24kb)
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; I/O MAP
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; I/O 0 (0x00 - 0x1F) LCD (uses 0x00 and 0x01)
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; I/O 1 (0x20 - 0x3F)
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; I/O 2 (0x40 - 0x5F)
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; I/O 3 (0x60 - 0x7F)
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; I/O 4 (0x80 - 0x9F)
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; I/O 5 (0xA0 - 0xBF)
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; I/O 6 (0xC0 - 0xDF)
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; I/O 7 (0xE0 - 0xFF)
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; MEMORY CONFIGURATION
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SYS_VAR_SPACE: EQU 0x8000
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DRV_VAR_SPACE: EQU 0x9000
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APP_VAR_SPACE: EQU 0xA000
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; SYSTEM CONFIGURATION
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IO_0: EQU 0x00
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IO_1: EQU 0x20
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IO_2: EQU 0x40
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IO_3: EQU 0x60
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IO_4: EQU 0x80
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IO_5: EQU 0xA0
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IO_6: EQU 0xC0
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IO_7: EQU 0xE0
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; LCD config (IO port 0)
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LCD_INSTR_REG: EQU IO_0
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LCD_DATA_REG: EQU IO_0 + 1
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; Keyboard config (IO port 1)
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KEYB_A0_REG: EQU IO_1 + %00000001
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KEYB_A1_REG: EQU IO_1 + %00000010
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KEYB_A2_REG: EQU IO_1 + %00000100
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KEYB_A3_REG: EQU IO_1 + %00001000
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KEYB_A4_REG: EQU IO_1 + %00010000
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; CONSTANTS
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SYSINIT_GREETING:
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DB "Pat80",0 ; null terminated string
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include 'driver_hd44780.asm'
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include 'driver_keyboard.asm'
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; System initialization
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Sysinit:
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call Lcd_init
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; position to line 2 char 3
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;ld b, 1
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;ld c, 1
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;call Lcd_locate
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; write characters to display
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ld bc, SYSINIT_GREETING
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call Lcd_print ; write string to screen
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; poll keyboard
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_poll_keyb:
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call Keyb_read
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jp poll_keyb
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