CS609 Quiz #1 Solution and Discussion

What is output of the following program;

#include<DOS.H>
union REGS regs;
void main (void )
{
regs.h.al = 0x99;
regs.h.ah = 0x00;
printf ("%x",regs.x.ax);
}

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@moaaz
The circular keyboard buffer starts at the address 40:1EH and contains 32 bytes. The
address 40:1AH stores the head of this circular buffer while the address 40:1CH stores the
tail of this buffer. If the buffer is empty the head and tail points at the same location as
shown in the diagram above.

@zaasmi

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Ref: Page 55 Handout

@zaasmi
32 bytes can be stored in Keyboard Buffer

Total No. of bytes that can be stored in Keyboard Buffer is____.
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If we want to produce the shrill voice from the speaker phone then we have to load the ___ divisor value at Port ___.
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if the following function,
keep(1, 1000);
is called in the TSR program, it means that ________ No. of bytes are reserved in the memory.

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In counter register bit no. 3 changes its value between 0 and 1 with in ____clock cycles
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Parameters in interrupts are passed through _________ .
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Getting interrupt vector refers to the operation which is used to read the _________ address stored with in vector.

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Int86() has ________ parameters.

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If we want to send printing on the printer then we have to perform following steps.
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The address of partition block on hard disk is ___________________________.

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