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DPMI 0.9+ - CALL REAL MODE PROCEDURE WITH IRET FRAME

AX = 0302h
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 at INT 31/AX=0300h)

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. 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. The real mode procedure must exit with an IRET. 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

See Also: AX=0300h

Category: DOS Extenders - Int 31h - D

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