Octagon Systems XE-700, Справочное руководство

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xxxxxxxx xxxxxxxxB
direction: 1=output, 0=input
DX ffffh
Return registers: Carry flag cleared if successful
Carry flag set if error
AL Error code
Comments: This function is used to initialize the
I/O before normal use.
Programming example:
/* Inline assembly code for Borland C++ 3.1 */
asm {
mov ax,0ef00h
mov di,00ffh /*port A all outputs,
init data=all 0’s */
mov bx,55ffh /*port B all outputs,
init data=55h*/
mov cx,0000h /*port C all inputs*
mov dx,0ffffh
int 17h
}
Write I/O
Function: efh
Subfunction: 01h
Purpose: To write a value to an I/O port.
Calling registers: AH efh
AL 01h
DI Port A mask and data
Mask Data
xxxxxxxx xxxxxxxxB
Mask: 1=bit to be changed
BX Port B mask and data
Mask Data
xxxxxxxx xxxxxxxxB
Mask: 1=bit to be changed
CX Port C mask and data
Mask Data
xxxxxxxx xxxxxxxxB
Mask: 1=bit to be changed
DX ffffh
Return registers: Carry flag cleared if successful
Carry flag set if error
AL Error code
Comments: This function is used to initialize the
I/O.
Programming example:
/* Inline assembly code for Borland C++ 3.1 */
asm {
mov ax,0ef01h
mov di,00ffh /*port A: no change */
mov bx,8000h /*port B: bit 7 set to 0*/
mov cx,0202h /*port C: bit 1 set to 0*/
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