Assembly Lang. – Intel 8086 Ch. 9 & 10 MUL
Description: Assembly Lang. Intel 8086 Ch. 9 10 MUL unsigned multiplication IMUL integer multiply for signed multiplication If 2 bytes r multiplied product is Word 16 bits If 2 words double-word 32 bits Byte form MUL source
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slide1. Assembly Lang. – Intel 8086 Ch. 9 & 10 MUL – unsigned multiplication
IMUL – integer multiply – for signed multiplication
If 2 bytes r multiplied product is Word [16 bits]
If 2 words … double-word [32 bits]<br>
slide2. Byte form –
MUL source ;source= register, mem; not const.
One no. is in ‘source’
Another no. is in AL
Product is in AX<br>
slide3. Word form
Source ; 16-bit reg/mem – not const.
AX
MSB in DX, LSB in AX [DX:AX]<br>
slide4. Q. A = 5xA – 12xB
A, B = word variables.
No overflow.
MOV AX, 5
IMUL A ;AX=5xA
MOV A,AX ;A=5A
MOV AX,12 ;AX=12
IMUL B ;AX=12B
SUB A,AX ;A=5A – 12B<br>
slide5. Q. Factorial that will compute N!<br>
slide6. DIV, IDIV DIV – divide – unsigned division
IDIV – integer divide
DIV divisor
Byte form:
Divisor 8-bt reg/mem
Dividend 16-bit in AX
After division, Quotient 8-bit in AL
…, Remainder 8-bit in AH 15 ÷ 3 = 5, 3 is the divisor<br>
slide7. Word form:
Divisor 16-bit reg/mem
Dividend 32-bit in DX:AX
After division, Quotient 16-bit in AX
…, Remainder 16-bit in DX<br>
slide8. Divide overflow<br>
slide9. Ch. 10 1-D array
DUP – to define arrays whose elements share a common initial value
E.g.,
GAMMA DW 100 DUP (0)
Sets up an array of 100 words, with each entry – initialized to 0.
GAMMA DW 100 DUP (?)
Sets up an array of 100 words, with each entry – UN-initialized.<br>
slide10. DUPs may be nested…<br>
IMUL – integer multiply – for signed multiplication
If 2 bytes r multiplied product is Word [16 bits]
If 2 words … double-word [32 bits]<br>
slide2. Byte form –
MUL source ;source= register, mem; not const.
One no. is in ‘source’
Another no. is in AL
Product is in AX<br>
slide3. Word form
Source ; 16-bit reg/mem – not const.
AX
MSB in DX, LSB in AX [DX:AX]<br>
slide4. Q. A = 5xA – 12xB
A, B = word variables.
No overflow.
MOV AX, 5
IMUL A ;AX=5xA
MOV A,AX ;A=5A
MOV AX,12 ;AX=12
IMUL B ;AX=12B
SUB A,AX ;A=5A – 12B<br>
slide5. Q. Factorial that will compute N!<br>
slide6. DIV, IDIV DIV – divide – unsigned division
IDIV – integer divide
DIV divisor
Byte form:
Divisor 8-bt reg/mem
Dividend 16-bit in AX
After division, Quotient 8-bit in AL
…, Remainder 8-bit in AH 15 ÷ 3 = 5, 3 is the divisor<br>
slide7. Word form:
Divisor 16-bit reg/mem
Dividend 32-bit in DX:AX
After division, Quotient 16-bit in AX
…, Remainder 16-bit in DX<br>
slide8. Divide overflow<br>
slide9. Ch. 10 1-D array
DUP – to define arrays whose elements share a common initial value
E.g.,
GAMMA DW 100 DUP (0)
Sets up an array of 100 words, with each entry – initialized to 0.
GAMMA DW 100 DUP (?)
Sets up an array of 100 words, with each entry – UN-initialized.<br>
slide10. DUPs may be nested…<br>