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Copyright © 2000 Hewlett-Packard Co. Linux and MS-DOS ABI Emulation 7-3
Ski IA-64 Simulator Reference Manual 1.0L
7.3 MS-DOS Application Environment
IA-32 application-mode programs “see” a limited MS-DOS environment. The MS-DOS environment is emulated by cre-
ating and initializing an MS-DOS Program Segment Prefix (PSP) and by setting up the stack pointer (iasp) and segmen-
tation registers. The arguments you gave with the iaload command, such as “iaload my_program foo bar baz”, are
placed in the PSP as if they were command line parameters.
Ski supports the MS-DOS “INT 20” call to terminate the simulated program and the “INT 21” system calls shown in
Table 7-3. When an IA-32 program makes an INT 21 call that’s not supported, the simulator stops the simulation and dis-
plays an error message.
7.4 Program I/O
Your program may need to read from standard in (stdin: file descriptor 0) and write to standard out (stdout: file descriptor
1) and standard err (stderr: file descriptor 2). As with all Linux programs, these file descriptors are connected, by default,
to your keyboard and screen. You can redirect them in the usual way: when you invoke Ski, use the < and > operators rec-
ognized by most Linux shells. For example, “bski -noconsole my_program foo bar baz < test_input
>simulated_output
” runs
bski
, loading the IA-64 program file my_program and passing it the arguments foo , bar
and baz via the argc/argv mechanism. Because no command file was provided via the -i flag (described in Section 2.5.1,
“Command Line Flags”),
bski
internally generates a run command followed by a quit command. The (simulated) pro-
gram reads on standard in from the file test_input and writes on standard out to the file simulated_output. Having
not been redirected, writes to standard err go to the default place, normally the terminal screen.
Table 7-3. MS-DOS System Calls (in Hexadecimal) Supported by Ski
00: terminate program 02: display character 08: read keyboard without echo
09: display string 2a: get date 2c: get time
30: get version number 3c: create file with handle 3d: open file with handle
3e: close file with handle 3f: read file or device 40: write file or device
44: device status control 44, sub-function 0: get device data 4c: end program
51: get PSP address 62: get PSP address (same as 51)