Further reading

Books by Jaggar [Jag95], Furber [Fur96], and Sloss et al. [Slo04] describe the ARM architecture. The ARM Web site, http://www.arm.com, contains a large number of documents describing various versions of ARM. Information on the PIC16F can be found at www.microchip.com. Information on the C55x and C64x can be found at http://www.ti.com.

Questions

Q2-1 What is the difference between a big-endian and little-endian data representation?

Q2-2 What is the difference between the Harvard and von Neumann architectures?

Q2-3 Answer the following questions about the ARM programming model:

Q2-4 How would the ARM status word be set after these operations?

Q2-5 What is the meaning of these ARM condition codes?

Q2-6 Explain the operation of the BL instruction, including the state of ARM registers before and after its operation.

Q2-7 How do you return from an ARM procedure?

Q2-8 In the following code, show the contents of the ARM function call stack just after each C function has been entered and just after the function exits. Assume that the function call stack is empty when main() begins.

int foo(int x1, int x2) {

    return x1 + x2;

}

int baz(int x1) {

    return x1 + 1;

}

int scum(int r) {

    for (i = 0; i = 2; i++)

       foo(r + i,5);

}

main() {

    scum(3);

    baz(2);

m}

Q2-9 Why are specialized instruction sets such as Neon or Jazelle useful?

Q2-10 Is the PIC16F a general-purpose register machine?

Q2-11 How large is the program counter stack in the PIC16F?

Q2-12 What two registers contribute to the program counter value?

Q2-13 What data types does the C55x support?

Q2-14 How many accumulators does the C55x have?

Q2-15 What C55x register holds arithmetic and bit manipulation flags?

Q2-16 What is a block repeat in the C55x?

Q2-17 How are the C55x data and program memory arranged in the physical memory?

Q2-18 Where are C55x memory-mapped registers located in the address space?

Q2-19 What is the AR register used for in the C55x?

Q2-20 What is the difference between DP and PDP addressing modes in the C55x?

Q2-21 How many stacks are supported by the C55x architecture and how are their locations in memory determined?

Q2-22 What register controls single-instruction repeats in the C55x?

Q2-23 What is the difference between slow and fast returns in the C55x?

Q2-24 How many functional units does the C64x have?

Q2-25 What is the difference between a fetch packet and an execute packet in the C64x?

Lab exercises

L2-1 Write a program that uses a circular buffer to perform FIR filtering.

L2-2 Write a simple loop that lets you exercise the cache. By changing the number of statements in the loop body, you can vary the cache hit rate of the loop as it executes. You should be able to observe changes in the speed of execution by observing the microprocessor bus.

L2-3 Compare the implementations of an FIR filter on two different processors. How do they compare in code size and performance?