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Then, why didn't the designer of the CPU make such that LDW instruction takes 5 clock cycles to begin with, rather than let the programmer insert 4 NOPs ? The answer is that you can insert other instructions other than NOPs as far as those instructions do not use the result of the LDW instruction above. By doing this, the CPU can execute additional instructions while waiting for the result of the LDW instruction to be valid, greatly reducing the total execution time of the entire program.

More on instructions with delay slots

The Table 3-5 in TI's instruction set description shows the execution of the instructions with delay slots in moredetail. The instructions with delay slots are multiply ( MPY , 1 delay slot), the load ( LDB, LDW etc. 4 delay slots) instructions, and the branch ( B , 5 delay slots) instruction.

The functional unit latency indicates for how many clock cycles each instructions actually use afunctional unit. All C62x instructions have 1 functionalunit latency, meaning that each functional unit is ready to execute the next instruction after 1 clock cycle regardlessof the delay slots of the instructions. Therefore, the following instructions are valid:

1 LDW .D1 *A10, A4 2 ADD .D1 A1,A2,A3

Although the first LDW instruction do not load the A4 register correctly while the ADD is executed, the D1 functional unit becomes available in the clock cycle right after the one in which LDW is executed.

To clarify the execution of instructions with delay slots, let's think of the following example of LDW instruction. Let's assume A10 = 0x0100 A2=1 , and your intent is loading A9 with the 32-bit word at the address 0x0104 . The 3 MV instructions are not related to the LDW instruction. They do something else.

1 LDW .D1 *A10++[A2], A92 MV .L1 A10, A8 3 MV .L1 A1, A104 MV .L1 A1, A2 5 ...

We can ask several interesting questions at this point:

  • What is the value loaded to A8 ? That is, in which clock cycle, the address pointer isupdated?
  • Can we load the address offset register A2 before the LDW instruction finishes the actual loading?
  • Is it legal to load to A10 before the first LDW finishes loading the memory content to A9 ? That is, can we change the address pointer before the 4 delay slotselapse?
Here are the answers:
  • Although it takes extra 4 clock cycles for the LDW instruction to load the memory content to A9 , the address pointer and offset registers ( A10 and A2 ) are read and updated in the clock cycle the LDW instruction is issued. Therefore, in line 2, A8 is loaded with the updated A10 , that is A10 = A8 = 0x104 .
  • Because the LDW reads the A10 and A2 registers in the first clock cycle, you are free to change these registers and do not affect the operationof the first LDW .
  • This was already answered above.

Similar theory holds for MPY and B (when using a register as a branch address) instructions. The MPY reads in the source values in the first clock cycle and loads themultiplication result after the 2nd clock cycle. For B , the address pointer is read in the first clock cycle, and the actual branching occurs after the5th clock cycle. Thus, after the first clock cycle, you are free to modify the source or the address pointer registers.For more details, refer Table 3-5 in the instruction set description or read the description of the individualinstruction.

Questions & Answers

What are the typical patterns of GDP for a high-income economy like the United States in the long run and the short run?
mwangala Reply
What are the limitation and significant of macroeconomic
Usman Reply
explain the significance of concerpt of opportunity cost in planning
Mwanaid Reply
what is meant by the price elasticity of demand?
Martine Reply
What are the limitations of macroeconomic and their segnificant
Usman Reply
Discuss the role of competition in stimulating economic growth?
Daniel Reply
competition stimulate economic growth because in such types of economy,they is no monopoly power every supplier will want to produce to meet customers choice which brings about quality production and attract invested and customers into such economy
Koka
competition creates Monopoly because of economy of scale. it's not antithesis but different side of same coin
toko
competition result in high economic growth since every firm will intend to provide quality services and products to meet customers needs and requirements unlike in Monopoly situation where a firm just provide what it want to resulting in large stock piles of unwanted products ,ie inefficiency, howev
Mark
microeconomics study part of the economy but macroeconomic study the whole economy
Olokun Reply
studying the whole economy, solving the problem of the economy and building up the economy
Olokun
micro means small while macro means large
Olokun
standard of living is the footsteps of an economy because it plays important role for country to have crucial view about their budget ,import and export
Olokun
it will be differ because economic agent will only take their views on some part of household
Olokun
can opportunity cost be zero
OBED Reply
how many types of transportation do we have
Jacob
yes. when a customer's purchasing power is high, he may have d ability to purchase all he needs, dt makes opportunity cost zero
George
please can give more explanation on this question
OBED
what are the factors production
PETER Reply
Labour capital entrepreneurs
Leta
Land,capital, labour,and the entrepreneur
Tantoh
I will like to know use of calculus in economics
JHUMA Reply
do they use it in economics?
Pranav
I want to know if I should take calculus or statistics and probability my senior year of highschool
Yahir
yes for example in monopolistic competitive market..... TR=TC* & THIS CALCULATED BY CHANGING( DERIVATIVE LAW) MR =MC ** WILL BE THE FORMULA THAT USE.
Leta
please in which topic in economic is the question coming from.
Tantoh
from PCF in economics
Leta
why is unitary proportional to responsiveness
Etim Reply
any tip for igcse economics exam?pls
Stacey Reply
well
The
What is a market
Divine Reply
what are the variables that affect demand
Divine
what are the variables that affect demand
Divine
what are the variables that affect demand
Divine
what are the variables that affect demand
Divine
what are the variables that affect demand
Divine
price of the related goods 2 price of the given commodity 3 income of the consumer 4 taste and preference 5 expectation in the future price
John
pls the taste and preference
Nas
explain briefly
Nas
a consumer taste and preference commodity changes for a time the man becomes
John
sorry sorry
John
is when the price of a commodity becomes high and can't afford example Samsung instead of iPhone
John
consumers who have high intense for goods will purchase the goods even if the price of that commodity increases because he or she preferred that commodity.people will be prefer iphone as its price increase
Yussif
as usual bad taste of preference is when a consumer regrets from one commodity to another in terms of the price
John
thanks alot
Nas
you're welcome
John
#Preference; #Income #Test
Dereje
#price Of Commodity #Income #Taste #Preference
Dereje
#Market is The Place Where Buyers And Sellers Are Exchanging Their Goods And service. #
Dereje
difference between macro and micro economics
Lawrence
Microeconomic Study about individual consumers market But Macroeconomis Study General economic Process Such As #Aggregate Demand #Aggregate Supples #GDp= #GNp
Dereje
nice so can u run down a brife discussion on GDP
Lawrence
good
Chinex
pls can someone differentiate between the perfectly elastic, perfectly inelastic and unitary
yhar Reply
and then again pls what are the types of elasticity, the methods of calculating it thank u
yhar
Perfectly inelastic is when the coefficient is equal to zero Unitary is when the coefficient is equal to one But am not sure if we have perfectly inelastic
John
I'm kind off confuse abt the PED, IED and co are they the types of elasticity we've
yhar
Yh the types are price elasticity cross and income elasticity of demand
John
do we've specific formulaes to calculate for each of them
yhar
yes. PED. changes in quantity demanded divided by changes in price
Vealmurugan
so pls what's the general name given to unitary, elastic n inelastic ? are the names given to the final result after doing the calculations?
yhar
P2-P1÷P1×100or Q2-Q1×Q1×100 PED
John
***tutor2u.net/economics/reference/price-elasticity-of-demand
Vealmurugan
They are elasticity coefficient
John
@John I don't get u well pls
yhar
whichone
John
P2-P1÷P1×100or Q2-Q1×Q1×100 PED @john pls tis is what m talking abt
yhar
Yh is the formula for PED
John
Pls are you having a for PED
John
thank u very
yhar
dy
Jobang
what is economics
Tayyeb
economics is a science which studies human behaviour as a relationship between ends and scarce means which have alternative use
John
is a science which study human behavior as a relationship between ends and scarce means which have alternative uses
Divine
yes this is because economic provide a body of knowledge on human economic principles under theories and these theories can be verified with real world data using science method in other words it was scientific method in arriving at solution identification of problem or basic data collection among
John
unitary ElasticWhen Elasticty =1 Perfectily Elastic When 0<1 inelastic when 0>
Dereje
Pls is anyone having the NovDec questions?
John Reply
No
Emmanuel
Difference between extinct and extici spicies
Amanpreet Reply
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
where are the solutions?
where are the solutions?

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Source:  OpenStax, Finite impulse response. OpenStax CNX. Feb 16, 2004 Download for free at http://cnx.org/content/col10226/1.1
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