165 lines
No EOL
6.3 KiB
NASM
165 lines
No EOL
6.3 KiB
NASM
; =============================================================================
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; Project : Custom BIOS / ROM
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; File : bda.asm
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; Author : frater
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;
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; License : GNU General Public License v3.0 or later (GPL-3.0+)
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;
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; This program is free software: you can redistribute it and/or modify
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; it under the terms of the GNU General Public License as published by
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; the Free Software Foundation, either version 3 of the License, or
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; (at your option) any later version.
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;
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; This program is distributed in the hope that it will be useful,
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; but WITHOUT ANY WARRANTY; without even the implied warranty of
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; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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; GNU General Public License for more details.
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;
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; You should have received a copy of the GNU General Public License
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; along with this program. If not, see <https://www.gnu.org/licenses/>.
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;
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; =============================================================================
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; compatible with IBM PC BIOS Data Area (BDA):
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; https://wiki.nox-rhea.org/back2root/ibm-pc-ms-dos/hardware/informations/bios_data_area
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;
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%define BDA_SEGMENT 0x0040 ; segment BDA
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; custom vars
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%define BDA_INFO_MEM_SIZE 0x0014 ; Memory size in Kbytes
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%define BDA_INFO_MEM_SEG BDA_INFO_MEM_SIZE+2 ; highest Memory Segment
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; video related information (compatible with VGA bios)
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%define BDA_VIDEO_CURR_MODE 0x0049
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%define BDA_VIDEO_COLUMNS 0x004A
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%define BDA_VIDEO_BUF_SIZE 0x004C
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%define BDA_VIDEO_OFS_PAGE 0x004E
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; keyboard related information
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%define BDA_KBD_HEAD 0x0080 ; byte
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%define BDA_KBD_TAIL 0x0081 ; byte
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%define BDA_KBD_FLAGS 0x0082 ; byte: bit0=shift, bit1=ctrl, bit2=alt, bit3=caps, bit4=ext(E0)
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%define BDA_KBD_BUF 0x0090 ; buffer circulaire (par ex 32 entrées *2 = 64 bytes)
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%define KBD_BUF_MASK 0x1F ; 32 entrées => index 0..31
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;
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; information relative à la souris
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;
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%define BDA_DATA_SEG 0x0050
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%define BKG_DWORDS_PER_LINE 1 ; 1 dword stocké par ligne
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%define BKG_LINES 16
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%define BKG_TOTAL_DWORDS (BKG_LINES * BKG_DWORDS_PER_LINE) ; 16
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%define BKG_TOTAL_BYTES (BKG_TOTAL_DWORDS * 4) ; 64
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struc mouse
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.buffer resb 4 ; i8042 input buffer
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.idx resb 1 ; index in the buffer
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.packetlen resb 1 ; max buffer len (3 ou 4)
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.status resb 1 ; mouse status (button etc)
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.wheel resb 1 ; if a packet size is 4; experimental
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.x resw 1 ;
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.y resw 1
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; cursor management
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.cur_x resw 1 ; preservation des x,y du background
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.cur_y resw 1
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.cur_addr_start resw 1 ; adresse de départ de la sauvegarde
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.cur_bank_add resw 1 ; + ou - 0x2000
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.cur_drawing resb 1
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.cur_visible resb 1
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.cur_seg resw 1 ; segment / offset of the pointer
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.cur_ofs resw 1
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.cur_mask resb 1 ; pixels mask (bit per pixel)
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.cur_bit_ofs resb 1 ; 0..7 bits d'offset (x&7)
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.bkg_saved resb 1 ; background saved
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alignb 4 ; alignement 4 bytes
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.bkg_buffer resd 16 ; buffer for saved background
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endstruc
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struc gfx
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.cur_x resw 1 ; x,y en pixel
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.cur_y resw 1
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.cur_offset resw 1 ; offset calculé pour le prochain caractère
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.cur_line_ofs resw 1 ; "interligne" +2000h ou -2000h
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; .cur_xbyte resb 1 ; x>>3 (0..79)
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.cur_shift resb 1 ; x&7 (0..7)
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; .cur_parity resb 1
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; .cur_color resb 1 ; 0 = texte en noir, autre = texte en blanc
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; .cur_trans resb 1 ; 0 = fond transparent, autre = fond inversé .txt_color
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.cur_mode resb 1 ;
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endstruc
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%define BDA_MOUSE 0x0000
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%define BDA_GFX (BDA_MOUSE + mouse_size)
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;
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; memory map
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;
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; 0x00000-0x003FF : IVT (1kB)
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; 0x00400-0x007FF : BDA (1kB) pour les options 'ROMS' carte graphique, etc...
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; 0x00800-0x009FF : Varibles custom.
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;
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; 0x03C00-0x08000 : stack segment
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; 0x
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; -----------------------------------------------------------------------------------
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; PC components I/O ports
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; -----------------------------------------------------------------------------------
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; controleur clavier/souris i8042 (AT-PS/2)
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%define i8042_PS2_DATA 0x60
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%define i8042_PS2_CTRL 0x64
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; PIC 8259 ports (Programmable Interrupt Controller)
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; PIC 1 : Master
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%define i8259_MASTER_CMD 0x20
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%define i8259_MASTER_DATA 0x21
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; PIC 2 : Slave
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%define i8259_SLAVE_CMD 0xA0
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%define i8259_SLAVE_DATA 0xA1
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; i8259 Commands
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%define ICW1_ICW4 0x01 ; Indicates that ICW4 will be present
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%define ICW1_SINGLE 0x02 ; Single (cascade) mode
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%define ICW1_INTERVAL4 0x04 ; Call address interval 4 (8)
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%define ICW1_LEVEL 0x08 ; Level triggered (edge) mode
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%define ICW1_INIT 0x10 ; Initialization - required!
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%define ICW4_8086 0x01 ; 8086/88 (MCS-80/85) mode
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%define ICW4_AUTO 0x02 ; Auto (normal) EOI
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%define ICW4_BUF_SLAVE 0x08 ; Buffered mode/slave
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%define ICW4_BUF_MASTER 0x0C ; Buffered mode/master
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%define ICW4_SFNM 0x10 ; Special fully nested (not)
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%define PIC_EOI 0x20
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; Remap : IRQ0..7 -> 0x08..0x0F, IRQ8..15 -> 0x70..0x77
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%define i8259_MASTER_INT 0x08
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%define i8259_SLAVE_INT 0x70
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%define IRQ_ENABLED 0x00
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%define IRQ_DISABLED 0x01
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; -----------------------------------------------------------------------------------
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; bda_setup
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; Initialise la BDA à zéro
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; -----------------------------------------------------------------------------------
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bda_setup:
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pusha
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push ds
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mov ax, BDA_DATA_SEG
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mov es, ax
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mov ax, 0x5F
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mov cx,0xFF
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xor di, di
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rep stosb ; clear BDA area
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pop ds
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popa
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ret |