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From: vlv@drux1.UUCP (Vaughn Vernon)
Newsgroups: net.micro.pc
Subject: Help with Video Retrace Code
Message-ID: <85@drux1.UUCP>
Date: Fri, 2-Aug-85 13:44:17 EDT
Article-I.D.: drux1.85
Posted: Fri Aug  2 13:44:17 1985
Date-Received: Sun, 4-Aug-85 08:48:37 EDT
Organization: AT&T Information Systems Laboratories, Denver
Lines: 29

Does anyone know the assembler code to do a check on the horizontal
retrace flag for the mono and color display on the PC to prevent
fuzz?

The code I really need is pretty simple I would suppose.  I would do
all the tricky stuff in 'C' (ie: set characters, attributes and the
offset into either the mono or color diplay for the line to be displayed)

I would like to be able to call an ASM routine like so:

	screen = (color ? 0xb8000:0xb0000);	/* paragraph 0 offset */
	for(row = 0; row < 25; row++)
		disp_row(buff[row], (screen + (row * 160));

I have reasons for doing one row at a time.

The routine would first check for a horizontal retrace and then blow
(movsb ?) the buff of char,attr,char,attr ... (160 bytes) to the
address that I passed.

I wish I could write such a beast!  Can someone help?  I can probably
do the data move my self if I can just get the retrace code.

					Thanks in advance,

					Vaughn Vernon
					AT&T ISL
					Denver, CO
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