Отправлено goshka 24 февраля 2003 г. 08:57

INT 31 P - DPMI 0.9+ - SIMULATE REAL MODE INTERRUPT
AX = 0300h
BL = interrupt number
BH = flags
bit 0: reset the interrupt controller and A20 line (DPMI 0.9)
reserved, must be 0 (DPMI 1.0+)
others: reserved, must be 0
CX = number of words to copy from protected mode to real mode stack
ES:(E)DI = selector:offset of real mode call structure (see #03148)
Return: CF clear if successful
real mode call structure modified (all fields except SS:SP, CS:IP
filled with return values from real mode interrupt)
CF set on error
AX = error code (DPMI 1.0+) (8012h,8013h,8014h,8021h)(see #03143)
protected mode stack unchanged
Notes: 16-bit programs use ES:DI as pointer, 32-bit programs use ES:EDI
CS:IP in the real mode call structure is ignored for this call,
instead, the indicated interrupt vector is used for the address
the flags in the call structure are pushed on the real mode stack to
form an interrupt stack frame, and the trace and interrupt flags are
clear on entry to the handler
DPMI will provide a small (30 words) real mode stack if SS:SP is zero
the real mode handler must return with the stack in the same state as
it was on being called
SeeAlso: AX=0302h,AX=FF01h,INT 21/AX=2511h,INT 21/AH=E3h"OS/286"
SeeAlso: INT 2C/AX=0026h,INT 2F/AX=FB42h/BX=000Dh
Format of DPMI real mode call structure:
Offset Size Description (Table 03148)
00h DWORD EDI
04h DWORD ESI
08h DWORD EBP
0Ch DWORD reserved (00h)
10h DWORD EBX
14h DWORD EDX
18h DWORD ECX
1Ch DWORD EAX
20h WORD flags
22h WORD ES
24h WORD DS
26h WORD FS
28h WORD GS
2Ah WORD IP
2Ch WORD CS
2Eh WORD SP
30h WORD SS

Зачем прерывание 1ah через него вызывается?
int PCI_Detect (void)
{
memset (&RMI,0,sizeof(RMI));
memset (&sregs,0,sizeof(sregs));
memset (®s,0,sizeof(regs));
RMI.EAX=0x0000b101;
regs.w.ax = 0x0300;
regs.h.bl = 0x1a;
sregs.es = FP_SEG(&RMI);
regs.x.edi = FP_OFF(&RMI);
int386x (0x31, ®s, ®s, &sregs );
return ((RMI.EDX == 0x20494350) && ((RMI.flags &1 )==0));
}

- ??????????????

• DPMI - это DOS protected memory interface. Чтобы самому не переключаться в real mode, наверное и используется. — ValterG   (24.02.2003 16:03, 307 байт)
  • А почему когда делаешь 1ah/b101 через 31h/300h все работает, а напрямую только часть eax(ax) заполняется? (Win98) — goshka   (24.02.2003 16:16, пустое)
    • Ну так вот и ответ - в Виндах надо делать через int 31. Никто и не говорил, что можно ДОС-вые прерывания использовать в Виндах напрямую. — ValterG   (24.02.2003 19:35, 93 байт)