Whee

A processor provides for one of the following ۲۴۶ of uring the

ISR VECTADDR hased 3. ६
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mechanism.

Processor Vector Address

tw

Fig. 4.6 (०) ISR_VECTADDRs for hardware inter

A system has internal devices like the on-chip timer and A/D CONVERT. In ഇ 1110110೧೧೧,
cach internal device interrupt source of source-group has ५ separate ISR ஹம்‌ ADDR address bach
external interrupt pin has രം ISR_VECTADDR, An example ts 8051. Figure 4 6/4) shows |
18% VECTADDRs for the hardware interrupt sources, A very commonly Used Method ۱× thar the
internal device (interrupt source ‏نه‎ 1111011110! source group) in the microcontroller aulogeneraies the
corresponding interrupt vector address, ISR. VECTADDR, Thus vector addresses ate specif 7
specific microcontroller or processor with that internal device. An internal hardware signal {rom the
device is sent for the interrupt source or source group.

. In 80x86 processor architecture, a software instruction, for example, /N7 ‏م‎ explicitly also defines the

type of interrupt and the type defines the ISR_VECTADDR., Figure 4.6(b) shows the 181९ VECTADDR,
with different vector addresses for different interrupt types. This mechanism results in the handling of
n number of exception handling routines or 158% for n interrupt 1905,

From a vector

ISR VECTADDR ட

ISR_VECTADDR 2 address either the 4
Devices vector addresses of interrupts ISR VECTADDR 3 | or 8-byte short ISA
from the hardware interrupt sources executes or a Jump

ISR_VECTADDR 4
ISR_VECTADOR 5

iNStructiOn executes |
for the long ISR |
codes at a new |
Starting address

(a)

| कषा? । Processor finds the ISR vector address
from the tour bytes at ISR_VECTADDRn

which computes from n | ५ Gites |
Each hardware or software interrupt source has a type ‏م‎ താത്‌
(0)

ISR (SWI handler) vector From the com ess,the |

mon vector address, the |

address. from here program Call to required SWI handler routine is |

0 using 4-byte instruction made as well as handler input-parameter |
another common vector address is computed

address for all SWI handlers ٠

(0)

rupt sources (0) ISR_VECTADDRs with different

vector address for different interrupt | i i 78
with common vector addresses fo Pt types using INT n instruction (८) The ISR_VECTAD

: r di ∙ 4 ⋅ 0
ಕರಗದು instruction Saf different exceptions, traps and signals using softwa

instead > ECT for
ടും ress and i there is a common ISR_VECTADDK
7 signal or ‘rap generated using SWI instruction. ISR that executes after vectors has