DOS ain't dead

indirect far jmp - calling old INT problem (Developers)

posted by RayeR , CZ, 13.05.2012, 17:15

> In general, I pass the entire original callers flags register, unchanged,
> to the old interrupt handler (whether I CALL it or JMP to it). I don't
> assume that the only thing that matters is one or two of the flags (like CF
> or ZF). In particular, modifying the Interrupt Flag or Direction flag can
> cause all kinds of problems, though modifying any flag other than the
> one(s) used to pass parameter(s) as defined by the API are potentially
> disastrous.

Well I did it this way:


INT     OLD_INT13H
push ax
pushf
pop ax
add sp,byte 8
push ax
sub sp,byte 6
pop ax
IRET


So all regs and flags are preserved but this is also +3 bytes increase size like above cm's code :P Damn it...

---
DOS gives me freedom to unlimited HW access.

Complete thread:

• indirect far jmp in NASM - RayeR, 10.05.2012, 10:46 (Developers)
  • indirect far jmp in NASM - RayeR, 10.05.2012, 13:16
    • indirect far jmp - ecm, 10.05.2012, 13:26
    • indirect far jmp in NASM - Rugxulo, 10.05.2012, 13:26
      • indirect far jmp in NASM - RayeR, 10.05.2012, 14:07
        • indirect far jmp - ecm, 10.05.2012, 15:17
          • indirect far jmp - RayeR, 11.05.2012, 00:47
            • indirect far jmp - ecm, 11.05.2012, 12:46
            • indirect far jmp - bretjohn, 11.05.2012, 18:53
              • indirect far jmp - RayeR, 11.05.2012, 19:31
                • indirect far jmp - bretjohn, 11.05.2012, 22:31
                  • indirect far jmp - ecm, 11.05.2012, 22:33
                    • indirect far jmp - RayeR, 12.05.2012, 00:33
                      • indirect far jmp - Arjay, 12.05.2012, 01:07
                        • indirect far jmp - ecm, 12.05.2012, 01:27
                          • indirect far jmp - Arjay, 12.05.2012, 11:09
                            • indirect far jmp - ecm, 12.05.2012, 21:18
                        • indirect far jmp - RayeR, 12.05.2012, 21:17
                          • indirect far jmp/call - Chaining Interrupt Service Routines - Arjay, 13.05.2012, 13:16
                      • indirect far jmp - calling old INT problem - RayeR, 13.05.2012, 04:01
                        • indirect far jmp - calling old INT problem - ecm, 13.05.2012, 04:27
                          • indirect far jmp - calling old INT problem - RayeR, 13.05.2012, 15:33
                            • indirect far jmp - calling old INT problem - bretjohn, 13.05.2012, 17:05
                              • indirect far jmp - calling old INT problem - RayeR, 13.05.2012, 17:15
                                • indirect far jmp - calling old INT problem - RayeR, 13.05.2012, 19:19
                                  • indirect far jmp - calling old INT problem - Rugxulo, 13.05.2012, 20:02
                                    • indirect far jmp - calling old INT problem - RayeR, 13.05.2012, 20:49
                                    • indirect far jmp - calling old INT problem - ecm, 13.05.2012, 23:49
                                  • indirect far jmp - calling old INT problem - ecm, 13.05.2012, 23:40
                                    • indirect far jmp - calling old INT problem - ecm, 14.05.2012, 00:07
                                      • indirect far jmp - calling old INT problem - RayeR, 14.05.2012, 01:19
                            • indirect far jmp - calling old INT problem - ecm, 13.05.2012, 23:44
                              • indirect far jmp - calling old INT problem - bretjohn, 14.05.2012, 18:30
                                • redundant override in "ss:bp" for clarity - ecm, 14.05.2012, 18:47
                                • indirect far jmp - calling old INT problem - RayeR, 14.05.2012, 18:50
                                  • indirect far jmp - calling old INT problem - bretjohn, 14.05.2012, 20:16
                                    • indirect far jmp - calling old INT problem - ecm, 14.05.2012, 20:21
                                      • indirect far jmp - calling old INT problem - bretjohn, 14.05.2012, 21:42
                                        • indirect far jmp - calling old INT problem - bretjohn, 15.05.2012, 18:45
                                          • indirect far jmp - calling old INT problem - ecm, 15.05.2012, 18:53
                                            • indirect far jmp - calling old INT problem - bretjohn, 15.05.2012, 20:13
                                              • indirect far jmp - calling old INT problem - RayeR, 17.05.2012, 01:25