HP IA-64, Ski Simulator manual MS-DOS Application Environment, Program I/O

Ski IA-64 Simulator Reference Manual 1.0L

7.3MS-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.

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)

7.4Program 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.

Copyright © 2000 Hewlett-Packard Co. Linux and MS-DOS ABI Emulation 7-3