printer port.txt

(编程控制示例）（为汇编代码） 此段代码为并口向打印机进行写数据

(编程控制示例）（为汇编代码）
// 此段代码为并口向打印机进行写数据，并发送控制信息。

#define LPT_CLEAR_MASK 0x40
#define LPT_STROBE_HI 0x0D
#define LPT_STROBE_LO 0x0C

#define LPT_STATUS_BITS 0xF8
#define LPT_BITS_INVERT 0x48
#define LPT_NOTBUSY 0x80
#define LPT_PAPEROUT 0x20
#define LPT_SELECT 0x10
#define LPT_NFAULT 0x08

#define LPT_TimeOut 0x01

void OutByte(ULONG dataport, BYTE databyte) {
#if x86
_asm {
mov dx, word ptr [dataport]
mov al, byte ptr [databyte]
out dx, al
out dx, al
add dx, 2
in al, dx
and al, LPT_CLEAR_MASK
mov cl, al
or al, LPT_STROBE_HI
out dx, al
out dx, al
out dx, al
out dx, al
or cl, LPT_STROBE_LO
mov al, cl
out dx, al
}
#else


WRITE_PORT_UCHAR((PUCHAR)dataport,databyte);

dataport+=2;
databyte = (READ_PORT_UCHAR((PUCHAR)dataport) & LPT_CLEAR_MASK)
| LPT_STROBE_HI;
WRITE_PORT_UCHAR((PUCHAR)dataport,databyte);

databyte = (READ_PORT_UCHAR((PUCHAR)dataport) & LPT_CLEAR_MASK)
| LPT_STROBE_LO;
WRITE_PORT_UCHAR((PUCHAR)dataport,databyte);

#endif
}

// 此段代码为读取打印机当前状态。
BYTE CheckStatus(unsigned port) {
BYTE bRet;

#if x86
_asm {
mov dx, word ptr[port]
Checkme:
in al, dx
mov ah, al
nop
nop
in al, dx
cmp al, ah
jnz Checkme
and ah, LPT_STATUS_BITS
xor ah, LPT_BITS_INVERT
test ah, LPT_PAPEROUT or LPT_NFAULT
jnz CS_HasError
test ah, LPT_SELECT
jz CS_HasError
and ah, LPT_NOTBUSY
jz CS_HasError
xor eax, eax
CS_HasError:
mov [bRet],al
}
#else

BYTE bStatus;
do {
bRet= bStatus= READ_PORT_UCHAR((PUCHAR)port);
} while (bStatus != READ_PORT_UCHAR((PUCHAR)port));
bStatus&= LPT_STATUS_BITS;
bStatus^= LPT_BITS_INVERT;

if (!(bStatus & (LPT_PAPEROUT | LPT_NFAULT)) &&
(bStatus & LPT_SELECT) && (bStatus & LPT_NOTBUSY))
bRet=0;
#endif
return bRet;
}

// The End