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Tutorial topic 4
Basic Assembly & Extended Pico Computer
[2001 Final]
1
Each instruction in a computer's instruction set…
(A)
Is implemented by a separate digital-logic building-block
(B)
Must load its operands from memory
(C)
Is interpreted by a hardware controller that sends control signals to digital logic building
blocks
(D)
Is distinguished from the other instructions by being written in a different font
[1]
[2001 Final]
2
The # placed before an assembler argument (as in mov a,#23) is there…
(A)
To perform the same function as the “*” pointer operator in C
(B)
To perform the same function as the “&” operator in C
(C)
To indicate the contents of a specific memory location (23 in the above example) should
be loaded into the accumulator
(D)
To indicate that a specific value (23 in the above example), not the contents of that
memory location, (memory location 23, in the example) should be loaded into the
accumulator
[1]
[2000 Final]
3
What does the instruction mov 17,@r0 do?
(A)
moves the contents of the memory location pointed at by r0 to memory location 17.
(B)
moves the data value 17 to the memory location pointed at by r0.
(C)
moves the value in r0 to memory location 17.
(D)
moves the contents of memory location 17 to the memory location pointed at by r0.
[1]
[2000 Final]
4
The braces in the programming language C (eg. if (A>B) { … } ) are used to group statements.
In assembler the equivalent construct…
(A)
is needed but only when using the simulator, the real processor doesn’t need them
(B)
isn’t needed
(C)
is the ORG – END construct
(D)
is always implemented with conditional jumps (eg JZ, JNZ …)
[1]
[2000 Final]
5
A computer processor…
(A)
generally divides data processing tasks amongst a number of independent units.
(B)
generally integrates control and data processing in a single monolithic unit.
(C)
uses a special register, capable of being incremented and parallel-loaded, called the
Program counter, to specify the next memory address which will be accessed.
(D)
is specifically designed to support a particular instruction set, and must be redesigned
from scratch if any alterations in the instruction set are made.
[1]
[1996 Final]
If the Pico-computer memory addresses 23, 50 and 51 contain the numbers 7, 1 and 23 respectively
(described in the table below), and the processor has already fetched the LDA (Load Accumulator)
instruction, then describe the register transfer operations, including any memory accessing, which will
occur during the remainder of the instruction. Be careful to specify the state of any registers that need to be
in a particular state prior to fetching the operand.
address
contents
mnemonic
23
7
data
....
50
1
LDA
instruction
51
23
direct operand
[10]