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What happen in registers Internaly using as in csl() function

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# 1  
Old 03-14-2007
What happen in registers Internaly using as in csl() function
Dear
i do not understand that function used for clear screen (given below)
cls
{
union REGS i,o;
i.h.ah=6;
i.h.al=0;
i.h.ch=0;
i.h.cl=0;
i.h.dh=24;
i.h.dl=79;
i.h.bh=7;
int86(16,&i,&o);
}
In Above function Registers are used(i think) but why and internally what the do for clearing the screen , i do not understand.
# 2  
Old 03-14-2007
This won't work in UNIX - it's ancient TURBO C code for PC's running under DOS.

The short answer is that this code calls the BIOS with interrupt #16, with some values
pushed into registers that tell it what to do with the screen driver.
# 3  
Old 03-15-2007
Quote:
Originally Posted by brain_full
Dear
i do not understand that function used for clear screen (given below)
cls
{
union REGS i,o;
i.h.ah=6;
i.h.al=0;
i.h.ch=0;
i.h.cl=0;
i.h.dh=24;
i.h.dl=79;
i.h.bh=7;
int86(16,&i,&o);
}
In Above function Registers are used(i think) but why and internally what the do for clearing the screen , i do not understand.
This is the ugly way of clearing your screen
Code:
system("clear");

really ugly!!! Smilie
# 4  
Old 03-15-2007
Code:
char escape=27;
printf("%c[2J", escape);

uses the tty driver and ANSI escape codes to clear the screen.
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