odify the following code to simulate a PEP/8 computer and instruction set for only the following instructions in the Image attached, to work in PEP/8 assembly language program : ORG $4000; start program ; start of program EQU MEMSIZE,$1000;size of memory ;Createing a structure to emulate the registers STRUCT Registers A RESW 1 ; register A X RESW 1 ; register X PC RESW 1 ; Program counter SP RESW 1 ; Stack pointer ENDS SECTION.BSS; declare variables
Modify the following code to simulate a PEP/8 computer and instruction set for only the following instructions in the Image attached, to work in PEP/8 assembly language
ORG $4000; start program ; start of program
EQU MEMSIZE,$1000;size of memory
;Createing a structure to emulate the registers
STRUCT Registers
A RESW 1 ; register A
X RESW 1 ; register X
PC RESW 1 ; Program counter
SP RESW 1 ; Stack pointer
ENDS
SECTION.BSS; declare variables
REGS Registers; registers
MEM RESW MEMSIZE; Memory array
ENDSEC
ORG $4000; start program
LDX #$FF ; Initialize X to highest memory address
STX REGS.SP; Set stack pointer to highest memory address
CLRA ; clear A
LDX #MEM; set X to point to the start of memory array
LDAB #10 ; load the value 10 to B
STAB 0,X ; Store 10 in first memory location
LDX #MEM+2 ; Set X to point to third memory location
LDAB #5 ; load 5 to B
STAB 0,X ; store 5 in the third memory location
LDX #MEM ; set X to point in the start of the array
LDAA 0,X ; Load the first number for memory to A
LDX #MEM+2 ; Set X to point to third memory location
ADDB 0,X ; Add the second number to B
STAA REGS.A ; store the result in A
HALT ; Halt
1. Use an array to represent the memory.
structure. I also recommend using an array of 16 bit values for A, X, PC, SP so
that you can use the r bit from the instructions to point directly to A or X. You do
NOT have to include the Status bits.
3. Use unions of structures to break up the registers and instructions into the correct
bits (for example, use a structure that can be unioned to break up the 8 bit
specifier into the following bit combos (4, 1, 3), (5, 3), (7, 1), (8). This will allow
you to instantly extract the instruction, register and addressing modes from each
instruction. Also use a union to break up the 16 bit operand into two 8 bit values.
4. Have the instructions be inputted either through the command line or better yet,
through a file, in the following format for each instruction, 6 Hexadecimal characters per instruction
5. After each instruction in the program is executed, output the PEP8 machine register values
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