1; VGA Palette Dumping TSR for MS-DOS - By: Peter Swinkels, ***2022***
2ALIGN 0x01, DB 0x90     ; Defines alignment.
3BITS 16                 ; Defines the segment size used by this program.
4ORG 0x0100              ; Indicates that all relative pointers to data are moved forward by 0x0100 bytes.
5
6REDIRECTED_FROM EQU 0x08  ; Defines the interrupt to be redirected.
7REDIRECTED_TO EQU 0xFF    ; Defines the redirected interrupt's new vector.
8
9JMP NEAR Main             ; Jumps to the main entry point.
10
11TSR:
12PUSHA                     ; Saves the registers.
13PUSH DS                   ;
14PUSH ES                   ;
15
16PUSH CS                   ; Restores the data segment register.
17POP DS                    ;
18
19%INCLUDE "PalDump.asm"    ; Includes the TSR module.
20
21POP ES                    ; Restores the registers.
22POP DS                    ;
23POPA                      ;
24
25INT REDIRECTED_TO         ; Calls the redirected interrupt.
26
27IRET                      ; Returns.
28EndTSR:
29
30Main:
31MOV AH, 0x09              ; Displays the TSR "start" message.
32MOV DX, TSR_Start_Msg     ;
33INT 0x21                  ;
34
35MOV AH, 0x35              ; Checks whether this TSR is already active by checking for a redirected interrupt.
36MOV AL, REDIRECTED_TO     ;
37INT 0x21                  ;
38MOV AX, ES                ;
39CMP AX, 0x0000            ;
40JNE IsActive              ;
41    CMP BX, 0x0000        ;
42    JNE IsActive          ;
43
44MOV AH, 0x34              ; Retrieves the address of the critical error and InDOS flags.
45INT 0x21                  ;
46MOV [CEInDOS_Offset], BX  ;
47MOV [CEInDOS_Segment], ES ;
48
49MOV AH, 0x35              ; Retrieves vector the vector for the interrupt to be redirected.
50MOV AL, REDIRECTED_FROM   ;
51INT 0x21                  ;
52
53MOV DX, BX                ; Places the retrieved vector at another interrupt.
54PUSH ES                   ;
55POP DS                    ;
56MOV AH, 0x25              ;
57MOV AL, REDIRECTED_TO     ;
58INT 0x21                  ;
59
60PUSH CS                   ; Sets this TSR's interrupt vector.

61POP DS                    ;
62MOV DX, TSR               ;
63MOV AH, 0x25              ;
64MOV AL, REDIRECTED_FROM   ;
65INT 0x21                  ;
66
67MOV AH, 0x09              ; Displays the TSR "activated" message.
68MOV DX, TSR_Activated_Msg ;
69INT 0x21                  ;
70
71MOV AX, 0x3100            ; Terminates and stays resident.
72MOV DX, EndTSR            ;
73ADD DX, 0x0F              ;
74SHR DX, 0x04              ;
75INT 0x21                  ;
76
77IsActive:                 ; 
78MOV AH, 0x09              ; Displays the TSR "already active" message.
79MOV DX, TSR_Activate_Msg  ;
80INT 0x21                  ;
81
82MOV AH, 0x4C              ; Quits if the TSR is already active.
83INT 0x21                  ;
84
85TSR_Activate_Msg DB "Already active!", 0x0D, 0x0A, "$"
86TSR_Activated_Msg DB "Activated.", 0x0D, 0x0A, "$"
87TSR_Start_Msg DB "VGA Palette Dumping TSR for MS-DOS v1.00 - by: Peter Swinkels, ***2022***"
88DB 0x0D, 0x0A
89DB "F12 = Dump the VGA palette."
90DB 0x0D, 0x0A
91DB "$"

1; VGA Palette Dumping module for TSR.
2
3MOV WORD BX, [CEInDOS_Offset]    ; Skips palette dumping if either the critical error or InDOS flag are set.
4MOV WORD ES, [CEInDOS_Segment]   ;
5ES                               ;
6CMP BYTE [BX - 0x01], 0x00       ;
7JNE Done                         ;
8ES                               ;
9CMP BYTE [BX], 0x00              ;
10JNE Done                         ;
11
12IN AL, 0x60             ; Skips palette dumping unless the F12 key is being pressed.
13CMP AL, 0x58            ;
14JNE Done                ;
15
16CMP BYTE [Busy], 0x00   ; Checks whether a dump is already in progress.
17JNE Done                ;
18
19MOV BYTE [Busy], 0x01   ; Sets the flag indicating a dump is in progress.
20
21MOV AH, 0x3C          ; Creates the output file.
22MOV CX, 0x00          ;
23LEA DX, OutputFile    ;
24INT 0x21              ;
25JC Done               ;
26
27MOV AX, BX            ; Closes the newly created output file.
28MOV AH, 0x3E          ;
29INT 21h               ;
30JC Done               ;
31
32MOV AH, 0x3D          ; Opens the output file for writing.
33MOV AL, 0x01          ;
34LEA DX, OutputFile    ;
35INT 0x21              ;
36JC Done               ;
37
38MOV BX, AX            ; Retrieves the filehandle.
39
40XOR AL, AL            ; Resets the color index.
41MOV [Color], AL       ;
42
43MOV DI, Palette       ; Sets the target to the palette buffer.
44Dump:
45   MOV AL, [Color]    ; Sets the color's index.
46   MOV DX, 0x3C8      ;
47   OUT DX, AL         ;
48
49   MOV CX, 0x03       ; Retrieves the RGB values.
50   GetRGB:            ;
51      MOV DX, 0x3C9   ;
52      IN AL, DX       ;
53      MOV [DI], AL    ;
54      INC DI          ;
55   LOOP GetRGB        ;
56
57   MOV AL, [Color]    ; Moves to the next color index or stops dumping when the last one has been reached.
58   CMP AL, 0xFF       ;
59   JE DumpFinished    ;
60   INC AL             ;

61   MOV [Color], AL    ;
62JMP Dump              ;
63
64DumpFinished:
65MOV AH, 0x40          ; Saves the retrieved palette.
66MOV CX, 0x300         ;
67MOV DX, Palette       ;
68INT 0x21              ;
69JC Done               ;
70
71MOV AH, 0x3E          ; Closes the output file.
72INT 21h               ;
73JMP NEAR Done         ;
74
75Busy DB 0x00
76CEInDOS_Offset DW 0x0000
77CEInDOS_Segment DW 0x0000
78Color DB 0x00
79MemorySegment DW 0x0000
80OutputFile DB "PalDump.dat", 0x00
81Palette Times 0x300 DB 0x00
82
83Done:
84MOV BYTE [Busy], 0x00   ; Clears the flag indicating a dump is progress.