TITLE Craps Simulation
; This is a 32-bit MASM Monte Carlo simulation program to estimate
; the probability of winning the dice game called craps.
INCLUDE Irvine32.inc
.data
iterReq BYTE "Craps Simulation - Enter number of iterations: ",0
first10 BYTE "First 10 Games - Detail:",0
oneSpace BYTE " ",0
iterStr BYTE " Iterations = ",0
winStr BYTE " Wins = ",0
winFirstStr BYTE " Wins on First Roll = ",0
loseFirstStr BYTE " Losses on First Roll = ",0
winsPointStr BYTE " Wins with Point = ",0
losesPointStr BYTE " Losses with Point = ",0
gameRollsStr BYTE " Rolls per Game. Total Rolls = ",0
iterations DWORD ?
die1 DWORD ?
die2 DWORD ?
diceTotal DWORD ?
point DWORD ?
wins DWORD 0
firstRollWins DWORD 0
firstRollLoses DWORD 0
winsWithPoint DWORD 0
losesWithPoint DWORD 0
totalRolls DWORD 0
.code
Main PROC
call Randomize ;Initialize random number seed
mov edx,OFFSET iterReq ;Request number of iterations from user
call WriteString
call ReadInt ;Get number of iterations entered by user
mov iterations, eax
call crlf
mov edx,OFFSET first10
call WriteString
call crlf
mov ecx,iterations
cmp iterations,10
jb FirstPlays
mov ecx,10
FirstPlays: ;display first 10 games (or less, is fewer iterations requested)
call PlayTheGame
loop FirstPlays
cmp iterations,11
jb DonePlaying
mov ecx,iterations
PlayGame: ;play the rest of the games
call PlayTheGames
loop PlayGame
DonePlaying:
call PrintStatistics ;display statistics
call crlf
exit
main ENDP
;==========================================================================================================
RollDice PROC ;Roll dice one time
mov eax,6
call RandomRange
mov die1,eax
mov eax,6
call RandomRange
mov die2,eax
mov eax,1
add eax,die1
add eax,die2
mov diceTotal,eax
call WriteDec
call PrintOneSpace
inc totalRolls
ret
RollDice ENDP
;==========================================================================================================
PlayTheGame PROC
call RollDice ;initial roll
cmp diceTotal,7
je FirstWins
cmp diceTotal,11
je FirstWins
cmp diceTotal,2
je FirstLoses
cmp diceTotal,3
je FirstLoses
cmp diceTotal,12
je FirstLoses
mov eax,diceTotal
mov point,eax
jmp RollAgain
FirstWins:
inc firstRollWins
inc wins
jmp GameOver
FirstLoses:
inc firstRollLoses
jmp GameOver
RollAgain: ;continue rolling if point
call RollDice
cmp diceTotal,7
je PointLoses
mov eax,point
cmp diceTotal,eax
je PointWins
jmp RollAgain
PointWins:
inc winsWithPoint
inc wins
jmp GameOver
PointLoses:
inc losesWithPoint
GameOver:
call crlf
ret
PlayTheGame ENDP
;==========================================================================================================
RollDices PROC ;Roll dice one time
mov eax,6
call RandomRange
mov die1,eax
mov eax,6
call RandomRange
mov die2,eax
mov eax,1
add eax,die1
add eax,die2
mov diceTotal,eax
inc totalRolls
ret
RollDices ENDP
;==========================================================================================================
PlayTheGames PROC
call RollDices ;initial roll
cmp diceTotal,7
je FirstWins
cmp diceTotal,11
je FirstWins
cmp diceTotal,2
je FirstLoses
cmp diceTotal,3
je FirstLoses
cmp diceTotal,12
je FirstLoses
mov eax,diceTotal
mov point,eax
jmp RollAgain
FirstWins:
inc firstRollWins
inc wins
jmp GameOver
FirstLoses:
inc firstRollLoses
jmp GameOver
RollAgain: ;continue rolling if point
call RollDices
cmp diceTotal,7
je PointLoses
mov eax,point
cmp diceTotal,eax
je PointWins
jmp RollAgain
PointWins:
inc winsWithPoint
inc wins
jmp GameOver
PointLoses:
inc losesWithPoint
GameOver:
ret
PlayTheGames ENDP
;==========================================================================================================
PrintOneSpace PROC
mov edx,OFFSET oneSpace
call WriteString
ret
PrintOneSpace ENDP
;==========================================================================================================
PrintStatistics PROC
mov edx,OFFSET iterStr
call WriteString
mov eax,iterations
call WriteDec
call crlf
call crlf
mov eax,wins
call PrintQuotient
mov edx,OFFSET winStr
call WriteString
mov eax,wins
call WriteDec
call crlf
call crlf
mov eax,firstRollWins
call PrintQuotient
mov edx,OFFSET winFirstStr
call WriteString
mov eax,firstRollWins
call WriteDec
call crlf
call crlf
mov eax,firstRollLoses
call PrintQuotient
mov edx,OFFSET loseFirstStr
call WriteString
mov eax,firstRollLoses
call WriteDec
call crlf
call crlf
mov eax,winsWithPoint
call PrintQuotient
mov edx,OFFSET winsPointStr
call WriteString
mov eax,winsWithPoint
call WriteDec
call crlf
call crlf
mov eax,losesWithPoint
call PrintQuotient
mov edx,OFFSET losesPointStr
call WriteString
mov eax,losesWithPoint
call WriteDec
call crlf
call crlf
mov eax,totalRolls
call PrintQuotient
mov edx,OFFSET gameRollsStr
call WriteString
mov eax,totalRolls
call WriteDec
call crlf
ret
PrintStatistics ENDP
;==========================================================================================================
PrintQuotient PROC
cmp eax,iterations
jb NoDivide1
cdq
div iterations
call WriteDec
mov eax,edx
jmp Done1
NoDivide1:
push eax
mov eax,0
call WriteDec
pop eax
Done1:
mov ebx,10
mul ebx
push eax
mov al,2Eh
call WriteChar
pop eax
mov ecx,6
Quotient:
cmp eax,iterations
jb NoDivide
cdq
div iterations
call WriteDec
mov eax,edx
jmp Done
NoDivide:
push eax
mov eax,0
call WriteDec
pop eax
Done:
mov ebx,10
mul ebx
loop Quotient
ret
PrintQuotient ENDP
END main
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