IPC@CHIP Documentation - SC12 @CHIP-RTOS V1.10

AH
ES:DI
Comments
Must be 0x20.
Address of the user error handler function (or zero to remove a previously installed handler).
The user is permitted to execute an error handler function if a fatal error occurs in either an application program or the @CHIP-
RTOS.
Note that this mechanism will (of course) fail if the user error handler code is itself overwritten (corrupt).
Only one error handler callback per system is supported. An application can remove its handler by calling this install function with a
zero (NULL) value in ES:DI, which is an advisable clean-up procedure at program exit.
The callback function must be of type huge _pascal with an errorcode input parameter (see the example function below). The
error codes conveyed by this input parameter are as follows:
1: Invalid processor opcode (usually caused by corrupted memory). The current task will be suspended.
2: Fatal kernel error (usually caused by corrupted memory or a task stack overflow)
3: Fatal internal TCP/IP error, current task will be suspended
4: TCP/IP stack reaches memory limit
5: TCP/IP memory allocation error
6: Ethernet bus error (hardware decfect)
7: Ethernet link error detected (cable not connected?)
8: Flash write error -> Flash defect ( Note: IPC@CHIP is no longer usable)
9: Low Memory error -> called if a memory allocation (system or user) failed.
In all cases (except errorcode 6,7 and 9) we recommend a reboot with BIOS interrupt 0xA0 0x21.
Important: Do not use any message printing inside your error handler if error code is 3 or 4,
because when Telnet is part of your stdio, your exit handler will hang inside the print call.
// Example for Borland C: This error handler reboots the system
void huge _pascal user_error_handler(int errorcode)
{
union REGS inregs;
union REGS outregs;
}
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// e.g. resetting outputs
outportb(0x600,0x00);
// rebooting the IPC@CHIP
inregs.h.ah = 0x21;
int86(0xA0,&inregs,&outregs);
// Installing the error handler function from program's main function
inregs.h.ah=0x20;
sregs.es =FP_SEG(user_error_handler);
inregs.x.di=FP_OFF(user_error_handler);
int86x(0xA0,&inregs,&outregs,&sregs);
Interrupt 0xA0 service 0x21: Rebooting the IPC@CHIP
Parameters
AH
This function works in the same way as the reboot shell command
0x21
Return Value
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