Add comments to explain each line of the program and briefly explain the purpose

Question

Add comments to explain each line of the program and briefly explain the purpose of the program. Determine the values of the symbols ‘main’, ‘bound’, ‘ipt’, and ‘loop’.           

BR             main

bound: .EQUATE 10    

ipt:      .EQUATE 0    

main: SUBSP        2, i       

DECI          ipt, s   

loop:     LDWA         ipt, s   

CPWA         bound, i

BRGE          endloop

ADDA          1, i      

STWA          ipt, s

DECO          ipt, s   

LDBA          '  ', i

STBA           charOut, d  

BR               loop

endloop: ADDSP        2, i

STOP

  .END

Explanation / Answer

BR             main. //BR is branch with return value,it goes to label main

bound: .EQUATE 10 //bound will check array index bound I.e.,size is 10,stack size is 10

ipt:      .EQUATE 0 //index starts from 0,stack pointer is at index 0

main: SUBSP        2, i //SUBSP=SP-operand ,i.e.,SP is a stack pointer that subracts i from the stack by popping 2 bytes

DECI          ipt, s //decimal input I.e.,ASCII value of s is 115

loop:     LDWA         ipt, s //push 115 at stack pointer index of ipt i.e.,0

CPWA         bound, i //value at index i is copied to index 10

BRGE          endloop //BRGP is brach if greater than or equal to (checks bound>=ipt)

ADDA          1, i //Adds 1 to the value at index i and stores the result in i

STWA          ipt, s //stores value at index s in address i

DECO          ipt, s //DECO is decimal output i.e.,stores 115 at input pointer i

LDBA          '  ', i //loads empty space(' ') at index i

STBA           charOut, d //stores operand d from symbolic table

BR               loop //executes loop ,until bound>=ipt

endloop: ADDSP        2, i //pushes operand i to stack by pushing 2 bytes

STOP //stops the execution

  .END

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