18- Indexed Addressing: The e address is specified by indicating a is a) TRUE se

ID: 2294155 • Letter: 1

Question

18- Indexed Addressing: The e address is specified by indicating a is a) TRUE set before/after either the stack pointer b) FALSE 19- a) TRUE b) FALSE Opcode: code ref erring to operation being performed 20- All opcodes must have Operands to which the operation is being performed to: a) TRUE b) FALSE 21- What are the contents of the topmost 3 bytes of the stack after the execution of the following code (fill in the table below) Instruction Length (in bytes) Assembly Code org $4000 lds #$3000 Idaa #$32 jsr mel mel psha 3 bytes :2 bytes ; 2 bytes 1 byte 2 bytes rever bra forever Stack Content k Address $2FFD $2FFE $2FFF $3000 $07 Page 5 of 12

Explanation / Answer

Address

Instruction

Comments

ORG $4000

Set starting value of location counter in code

$4000

lds #$3000

Load stack pointer with immediate value. SP = $3000

$4003

ldaa #$32

Load accumulator A with immediate value. A = $32

$4005

jsr mel

Jump to subroutine & return address ($4007) saved on stack

$4007

mel psha

Push A on stack. A=$32

forever bra forever

Remain here infinitely

Stack Address

Stack Content

$2FFD

$2FFE

$32

$2FFF

$07

$3000

$40