DOS ain't dead - indirect far jmp - calling old INT problem

indirect far jmp - calling old INT problem (Developers)

posted by RayeR , CZ, 13.05.2012, 19:19

OK, I optimized it a bit, now just 1 byte greater than old code, not bad, I leave it...
NEW_INT13H: ;INT XX do CLI, PUSH F,CS,IP (6B), SP=x-6 PUSHF ;store flags (2B), SP=x-8 CMP DL,ROMDISK_DRIVE;related to our disk ? JE @NEW_INT13H_HUB ;if yes continue below else POPF ;restore flags (2B), SP=x-6 INT OLD_INT13H ;call old INT 13h handler, SP=x-6 PUSH BP ;store BP (2B), SP=x-8 MOV BP,SP ;set BP to current SP, BP=SP=x-8 PUSHF ;store flags (2B) that was returned by old INT 13h handler, SP=x-10 POP WORD [SS:BP+6] ;replace previously saved flags of INT caller on stack by current flags, SP=x-8 POP BP ;restore BP (2B), SP=x-6 IRET ;return from ISR, do POP IP,CS,F (6B), SP=x-0

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DOS gives me freedom to unlimited HW access.

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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