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/*
* VBMouse - Interface to some DOS int 21h services
* Copyright (C) 2022 Javier S. Pedro
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef INT21DOS_H
#define INT21DOS_H
#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>
#include <dos.h>
#include "sassert.h"
#define DOS_PSP_SIZE 256
enum dos_error {
DOS_ERROR_SUCCESS = 0,
DOS_ERROR_INVALID_FUNCTION = 1,
DOS_ERROR_FILE_NOT_FOUND = 2,
DOS_ERROR_PATH_NOT_FOUND = 3,
DOS_ERROR_TOO_MANY_OPEN_FILES = 4,
DOS_ERROR_ACCESS_DENIED = 5,
DOS_ERROR_INVALID_HANDLE = 6,
DOS_ERROR_ARENA_TRASHED = 7,
DOS_ERROR_NOT_ENOUGH_MEMORY = 8,
DOS_ERROR_INVALID_BLOCK = 9,
DOS_ERROR_BAD_ENVIRONMENT = 10,
DOS_ERROR_BAD_FORMAT = 11,
DOS_ERROR_INVALID_ACCESS = 12,
DOS_ERROR_INVALID_DATA = 13,
DOS_ERROR_OUT_OF_MEMORY = 14,
DOS_ERROR_INVALID_DRIVE = 15,
DOS_ERROR_CURRENT_DIRECTORY = 16,
DOS_ERROR_NOT_SAME_DEVICE = 17,
DOS_ERROR_NO_MORE_FILES = 18,
DOS_ERROR_WRITE_PROTECT = 19,
DOS_ERROR_BAD_UNIT = 20,
DOS_ERROR_NOT_READY = 21,
DOS_ERROR_BAD_COMMAND = 22,
DOS_ERROR_CRC = 23,
DOS_ERROR_BAD_LENGTH = 24,
DOS_ERROR_SEEK = 25,
DOS_ERROR_NOT_DOS_DISK = 26,
DOS_ERROR_SECTOR_NOT_FOUND = 27,
DOS_ERROR_GEN_FAILURE = 31,
DOS_ERROR_HANDLE_EOF = 38,
DOS_ERROR_HANDLE_DISK_FULL = 39,
DOS_ERROR_FILE_EXISTS = 80,
DOS_ERROR_CANNOT_MAKE = 82,
};
// General functions
static inline void dos_print_char(char c);
#pragma aux dos_print_char = \
"mov ah, 0x02" \
"int 0x21" \
__parm [dl] \
__modify [ah]
static inline uint8_t dos_read_char(void);
#pragma aux dos_read_char = \
"mov ah, 0x08" \
"int 0x21" \
__value [al] \
__modify [ax]
static inline void dos_print_string(const char *s);
#pragma aux dos_print_string = \
"mov ah, 0x09" \
"int 0x21" \
__parm [dx] \
__modify [ah]
static inline uint16_t dos_get_version(void);
#pragma aux dos_get_version = \
"mov ah, 0x30" \
"int 0x21" \
__value [ax] \
__modify [bx cx]
// Memory manipulation functions
typedef __segment segment_t;
enum dos_allocation_strategy {
DOS_FIT_FIRST = 0,
DOS_FIT_BEST = 1,
DOS_FIT_LAST = 2,
DOS_FIT_HIGH = 0x80,
DOS_FIT_HIGHONLY = 0x40,
};
/** Converts bytes to paragraphs (16 bytes), rounding up. */
static inline unsigned get_paragraphs(unsigned bytes)
{
return (bytes + 15) / 16;
}
static unsigned dos_query_allocation_strategy(void);
#pragma aux dos_query_allocation_strategy = \
"mov ax, 0x5800" \
"int 0x21" \
__value [ax]
static int dos_set_allocation_strategy(unsigned strategy);
#pragma aux dos_set_allocation_strategy = \
"clc" \
"mov ax, 0x5801" \
"int 0x21" \
"jc end" \
"mov ax, 0" \
"end:" \
__parm [bx] \
__value [ax]
static bool dos_query_umb_link_state(void);
#pragma aux dos_query_umb_link_state = \
"mov ax, 0x5802" \
"int 0x21" \
__value [al]
static int dos_set_umb_link_state(bool state);
#pragma aux dos_set_umb_link_state = \
"clc" \
"mov ax, 0x5803" \
"int 0x21" \
"jc end" \
"mov ax, 0" \
"end:" \
__parm [bx] \
__value [ax]
/** Allocates a new DOS segment.
* @returns either the allocated segment or 0 if any error. */
static __segment dos_alloc(unsigned paragraphs);
#pragma aux dos_alloc = \
"clc" \
"mov ah, 0x48" \
"int 0x21" \
"jnc end" \
"mov ax, 0xB" \
"end:" \
__parm [bx] \
__value [ax]
/** Frees DOS segment. */
static void dos_free(segment_t segment);
#pragma aux dos_free = \
"mov ah, 0x49" \
"int 0x21" \
__parm [es] \
__modify [ax]
/** Sets a given PSP as the current active process. */
static void dos_set_psp(segment_t psp);
#pragma aux dos_set_psp = \
"mov ah, 0x50" \
"int 0x21" \
__parm [bx] \
__modify [ax]
#endif // INT21DOS_H
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