Main code for Program 9

program9_starter.pep

BR main
;Do not modify code before this point!


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;BEGIN INPUTTO (get user input by reference)
inputTo: nop0 ;pretty input getter

;any equates you need for local variables

 ;CODE formal parameter #2h
ITPasses: .equate ;FINISH CODE size of frame for inputTo arguments+return values
ITArg: .equate ;FINISH CODE caller's view of input's argument

;prompt for, get, and acknowledge input
;store it at the place POINTED TO by our argument
RET0
;date for use by inputTo procedure
prompt: .ASCII "Please enter a number.\n\x00"
receipt1: .ascii "Thank you for entering [\x00"
receipt2: .ascii "]\n\x00"
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;END INPUTTO (get user input by reference)




;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;BEGIN FCTRL (factorial)
fctrl: nop0 ;factorial

;any equates you need for local variables

 ;CODE formal parameter #2d
 ;CODE return value #2d
FPasses: .equate ;FINISH CODE size of frame for fctrl arguments+return values
FArg: .equate ;FINISH CODE
FRet: .equate ;FINISH CODE

;if(n<=1)
;return 1

;else
;recCall = factorial(n-1)
;return n*recCall [n*factorial(n-1)]
RET0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;BEGIN FCTRL (factorial)






;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;BEGIN MULTIPLY
multiply: nop0; multiply (NEEDS TO BE MODIFIED - currently this ADDs instead of MULTiplies!)

MLocals: .equate 0 ;size of frame for multiply local variables (this implementation uses none)

mulPar1: .equate 2 ;formal parameter #2d
mulPar2: .equate 4 ;formal parameter #2d
mulRetV: .equate 6 ;return value #2d
MPasses: .equate 6 ;size of frame for multiply arguments+return values
MArg1: .equate -6 ;caller's view of arg1
MArg2: .equate -4 ;caller's view of arg2
MRet: .equate -2 ;caller's view of return value

subsp MLocals,i ;allocate nothing

;return arg1+arg2
lda mulPar1,s
adda mulPar2,s
sta mulRetV,s 

addsp MLocals,i ;deallocate nothing
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;END MULTIPLY
RET0




;Do not modify code past this point!


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;BEGIN MAIN
main: nop0 
theReslt: .equate 0 ;local variable #2d
theInpt: .equate 2 ;local variable #2d
mainFram: .equate 4 ;size of local stack for main

SUBSP mainFram,i ;allocate #theInpt #theReslt 

stro welcome,d ;welcome message

;inputTo(theInput) [passed by reference]
movspa ;load stack pointer to accumulator
adda theInpt,i ;offset by stack-relative address
sta ITArg,s 
subsp ITPasses,i ;push #inputPar
call inputTo,i ;get user input
addsp ITPasses,i ;pop #inputPar

stro notice1,d ;going to find factorial message

lda theInpt,s ;prepare argument of factorial
sta FArg,s 
subsp FPasses,i ;push #fctRetV #fctArg 
call fctrl,i
addsp FPasses,i ;pop #fctArg #fctRetV 
lda FRet,s 
sta theReslt,s ;store result locally

deco theReslt,s ;display result

ADDSP mainFram,i ;deallocate #theReslt #theInpt 

stro notice2,d ;going to repeat message
BR main

STOP
welcome: .ascii "Welcome to the program!\n\x00"
notice1: .ascii "We will now figure out the factorial of your number! It is... \x00"
notice2: .ascii "\n\nThat was fun. Let's do it again!\n\n\n\n\n\x00"
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;END MAIN
.end