ECE 330
Due: 9/13/2010 a.
b.
c.
d.
Homework 3 Fall 2010
1.
Create macros that implement the following instructions. These macros should not use any registers other than those specified as operands. Write a program that utilizes each of the following macros. Show before and after snapshots of registers that confirms validity.
decrement
Operation: rA ←  rA - 1
Assembler Syntax: decr rA decr r6 Example:
rotate right immediate
Operation: rB ←  rA rotated right IMM5 bit positions
Assembler Syntax: rori rB, rA, IMM5
Example: rori r6, r7, 3
halt execution
Operation: PC ←  PC
Assembler Syntax: halt halt Example:
one’s complement
Operation: rB ←  ~rA
Assembler Syntax: comp rB, rA
Example: comp r2, r8
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ECE 330 Homework 3 Fall 2010
Due: 9/13/2010
2.
Create macros that implement the following instructions. These macros may require the usage of additional registers. When a temporary register is needed for temporary values use register r1 . Write a program that utilizes each of the following macros. Show before and after snapshots of registers that confirms validity. a.
b.
toggle bit immediate
Operation: rB ←  rA
31..IMM5+1
: ~rA
IMM5
: rA
IMM5-1..0
Assembler Syntax: togglebiti rB, rA, IMM5 togglebiti r2, r8, 7 Example:
clear bit immediate
Operation: rB ←  rA
31..IMM5+1
: 0 : rA
IMM5-1..0
Assembler Syntax: clearbiti rB, rA, IMM5
Example: clearbiti r2, r8, 7 c.
set bit immediate
Operation: rA
IMM5
←  1
Assembler Syntax: setbiti rA, IMM5
Example: setbiti r2, 7 d.
test for bit set immediate
Operation: if rA
IMM5
= 1 then rB ≠ 0 other wise rB = 0
Assembler Syntax: testbiti rB, rA, IMM5
Example: testbiti r2, r8, 7
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ECE 330 Homework 3 Fall 2010
Due: 9/13/2010
3.
For the assembly code, memory and registers shown below, answer the following questions.
# file: hw3_3.s
.text
.global _start
_start: r8,COUNT r8,0(r8) r9,LIST r2,r0
LOOP: r8,r0,LOOP_END
ldw
add r8,r8,1
addi r2,r2,r3
subi r9,r9,4
LOOP
LOOP_END: r9,SUM r2,0(r9)
.
.data
0xaaaaaaaa
COUNT:
LIST: .word 2,3,5,7,11,13,17
LIST_END:
SUM:
0xffffffff
.end a.
What is the value of the label LOOP ? b.
What is the value of the label LOOP_END ? c.
What is the value of the label COUNT ? d.
What is the value of the label LIST ? e.
What is the value of the label LIST_END ? f.
What is the value of the label SUM ? g.
What is the next assembly instruction to be executed? h.
What is the memory address referenced by the label COUNT ? i.
What is the value of memory (word) referenced by the label COUNT ? j.
What is the address of memory that will change as a result of running this program? k.
What is the new value (word) in memory that changes? l.
What is the machine instruction referenced by the label LOOP ?
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