I am having some difficulty porting the following MIPS32 assembly program to a 64-bit equivalent.
The main issue that I am facing is the following line:
bgtz $s2, loop ; Branch from "loop" on "$s2" greater than zero.
I am not sure why this line causes an error? The instruction should be in MIPS64.
MIPS32
# Description of Program: Computes first 25 Fibonacci numbers and store in an array.
# Description of Register Usage:
# $s0 = Memory address
# $s1 = Array Size
# $s2 = Counter
# $s3 = F[n] initialized at 1
# $s4 = F[n - 1]
# $s5 = F[n - 2]
.data ## DECLARATIONS ##
size: .word 25 # Size of the array or limit.
array: .word 0 : 25 # Create an array of words to store the 1st 25 Fibonacci numbers.
.text ## CODE SECTION ##
main: la $s1, size # Load address of size variable.
la $s0, array # Load address of the array.
lw $s1, 0($s1) # Load size of the array.
addi $s2, $s1, -2 # [Counter = Array Size - 2] Counter for loop.
li $s3, 1 # 1 is the 2nd value of the Fibonacci Sequence.
sw $zero, 0($s0) # F[0] = 0; Store 1st value.
sw $s3, 4($s0) # F[1] = 1; Store 2nd value.
loop: lw $s4, 0($s0) # Get F[0] from memory and assign it to F[n - 2].
lw $s5, 4($s0) # Get F[1] from memory and assign it to F[n - 1].
add $s3, $s4, $s5 # F[n] = F[n - 1] + F[n - 2].
sw $s3, 8($s0) # Store the new F[n] into memory at the next availible location.
addi $s0, $s0, 4 # Start memory address at the new F[n].
addi $s2, $s2, -1 # [Counter = Counter - 1] Counter is initialized at 23.
bgtz $s2, loop # Loop until the counter finally reaches zero.
exit: li $v0, 10 # System call for exit.
syscall # Exit...
###################### MEMORY DUMP ########################
# 0x10010000 0x00000019 0x00000000 0x00000001 0x00000001 #
# 0x10010010 0x00000002 0x00000003 0x00000005 0x00000008 #
# 0x10010020 0x0000000d 0x00000015 0x00000022 0x00000037 #
# 0x10010030 0x00000059 0x00000090 0x000000e9 0x00000179 #
# 0x10010040 0x00000262 0x000003db 0x0000063d 0x00000a18 #
# 0x10010050 0x00001055 0x00001a6d 0x00002ac2 0x0000452f #
# 0x10010060 0x00006ff1 0x0000b520 0x00000000 0x00000000 #
# 0x10010070 0x00000000 0x00000000 0x00000000 0x00000000 #
###########################################################
MIPS64
.data ;; DECLARATIONS
size: .word 25 ; Size of the array or limit.
array: .space 100 ; Create an array of words to store the 1st 25 Fibonacci numbers.
.text ;; CODE SECTION
main: ori $s1, $zero, size ; Load address of size variable.
ori $s0, $zero, array ; Load address of the array.
lw $s1, 0($s1) ; Load size of the array.
addi $s2, $s1, -2 ; [Counter = Array Size - 2] Counter for loop.
ori $s3, $zero, 1 ; 1 is the 2nd value of the Fibonacci Sequence.
sw $zero, 0($s0) ; F[0] = 0; Store 1st value.
sw $s3, 4($s0) ; F[1] = 1; Store 2nd value.
loop: lw $s4, 0($s0) ; Get F[0] from memory and assign it to F[n - 2].
lw $s5, 4($s0) ; Get F[1] from memory and assign it to F[n - 1].
add $s3, $s4, $s5 ; F[n] = F[n - 1] + F[n - 2].
sw $s3, 8($s0) ; Store the new F[n] into memory at the next available location.
addi $s0, $s0, 4 ; Start memory address at the new F[n].
addi $s2, $s2, -1 ; [Counter = Counter - 1] Counter is initialized at 23.
bgtz $s2, loop ; Loop until the counter finally reaches zero.
exit: halt ; Exit...
It should be bgez in EduMIPS64.