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INT 21 - DOS 2+ - LOAD OR EXECUTE (EXEC)
|
Input |
DOS1 |
N |
DOS2 |
Y |
DOS3 |
Y |
DOS5 |
Y |
Output |
|
AX |
4Bh |
Subfunction |
Error
Code |
AX |
|
|
|
|
|
|
BX |
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CX |
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CX |
|
DS:DX |
File
Name |
|
|
DX |
|
ES:BX |
Parameter
Block |
Set
if Error |
CF |
Subfunction: 0 = Load and execute program
1 = Load but do not execute (internal, DOS 3.x, DesqView)
2 = Load but do not execute (internal, DOS 2.x only)
3 = Load overlay; do not create PSP
Parameter Block:
AL = 0
00h WORD Segment of environment (0 = use current)
02h DWORD Command line
06h DWORD FCB 1
0Ah DWORD FCB 2
AL = 1
Process ID set to new program's PSP; get with function 62h
00h WORD Segment of environment (0 = use current)
02h DWORD Command line
06h DWORD FCB 1
0Ah DWORD FCB 2
0Eh DWORD Will hold SS:SP on return
12h DWORD Will hold program entry point (CS:IP) on return
AL = 2
New program's initial stack and entry point returned in registers
00h WORD Segment of environment (0 = use current)
02h DWORD Command line
06h DWORD FCB 1
0Ah DWORD FCB 2
AL = 3
00h WORD Segment load address
02h WORD Segment relocation factor
Note: DOS 2.x destroys all registers, including SS:SP
See Also 3Dh 4Ah 4Dh 59h FCB PSP EXE File Header Error Codes |