Deleted compiled file

.gitignore

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+mult3or5/main
+evenFibonacci/main
+*/main

README.md

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+## Project Euler Solutions
+
+This repository contains my solutions to the [Project Euler problems](https://projecteuler.net/archives), written - to the best of my abilities - in 32-bit ARM Assembly.
+
+The Assembly code was written and tested on a Raspberry Pi 3B, and contains C code to facilitate formatted input and output.

evenFibonacci/README.md

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+## Even Fibonacci Numbers
+
+This directory contains my solution to the ['Even Fibonacci numbers' problem](https://projecteuler.net/problem=2).

evenFibonacci/main.c

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+#include <stdio.h>
+
+int evenFib();
+
+void main() {
+	printf("%d\n",evenFib());
+	return;
+}

evenFibonacci/main.s

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+.global evenFib
+
+.section .text
+evenFib:
+init:
+	PUSH {R4}		@The ARM calling convention only allows callee functions to use R0-R3. Since I need R4 as well, I am going to push R4 onto the stack, and pop it off when I am done using it.
+	MOV R0,#0		@Return value - where all the addition is going to happen to
+	LDR R4,=#4000000	@ARM doesn't allow you to 'MOV' constants greater than 8 bits. To get around that, we use the LDR instruction, which lets the assembler place the value in memory, and then load it from there.
+	MOV R1,#1		@Main fibonacci number
+	MOV R2,#0		@Used to hold temporary values when incrementing the main fibonacci number
+	MOV R3,#0		@Previous fibonacci number - This will be 0 at the start
+loop:
+
+incr:
+	MOV R2,R1	@Store the current fibonacci number in R2
+	ADD R1,R1,R3	@Add the previous fibonacci number with the current one
+	MOV R3,R2	@Move R2 (the 'old current' fibonacci number) into R3
+checkbnd:
+	CMP R1,R4	@Check if R1 is greater than the upper bound for fibonacci numbers
+	BGE return	@If it is, then we return
+
+checkparity:		@Parity - The fact of being even or odd.
+	TST R1,#0x1	@Equivalent of an ANDS operation, but the result is discarded. In this case, we are checking if R1's parity by checking the last bit, which would be set to 0 if it is even, and 1 if it is odd.
+	BNE loop	@If R1 is odd, don't do the addition. Instead, go back to the loop, where we move on to the next fibonacci number.
+
+
+isEven: @The program goes here if R1 is even
+	ADD R0,R0,R1	@Add the fibonacci number to R0
+	B loop
+
+return:
+	POP {R4}	@Pop the R4 that we pushed onto the stack earlier
+	BX lr
+
+.section .data

mult3or5/README.md

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+## Multiples of 3 or 5
+
+This directory contains my solution to the ['Multiples of 3 or 5' problem](https://projecteuler.net/problem=1).

mult3or5/main.s

@@ -2,39 +2,34 @@
 .section .text
 
 func:
-	MOV R0,#3
-	MOV R1,#5
-	MOV R2,#0
+init:
+	MOV R0,#3  @Move 3 to R0
+	MOV R1,#5  @Move 5 to R1
+	MOV R2,#0  @Move 0 to R2
+	MOV R3,#1000  @The value to compare with
 loop:
-checkeq:
-@	CMP R0,R1
-@mult15:
-@	ADDEQ R2,R2,R0
-@	BEQ incr
-else:
 add5:
-	ADD R2,R2,R1
-	ADD R1,R1,#5
+	ADD R2,R2,R1  @Add R1 to R2
+	ADD R1,R1,#5  @Increment R1 by 5
 add3:
-	ADD R2,R2,R0
-	ADD R0,R0,#3
+	ADD R2,R2,R0  @Add R0 to R2
+	ADD R0,R0,#3  @Increment R0 by 3
 
 check3:
-	CMP R0,#1000
-	BLT check5
-	BGE rmv15
+	CMP R0,R3  @Is R0 less than 1000?
+	BGE rmv15  @If the multiple of 3 is greater than 1000, go to rmv15
 
 check5:
-	CMP R1,#1000
-	BLT loop
-	BGE add3
+	CMP R1,R3  @Is R1 less than 1000?
+	BLT loop  @If true, go back to loop
+	BGE add3  @If the multiple of 5 reaches 1000, go back to add3 instead of loop - Continue adding multiples of 3, because those wouldn't have reached 1000 yet
 
 rmv15:
-	MOV R0,#15
+	MOV R0,#15  @The loop that follows is intended to subtract multiples of 15, which would have been added twice - 3, 6, 9, 12, [15], 18 ; 5, 10, [15], 20
 loop2:
 	SUB R2,R2,R0
 	ADD R0,R0,#15
-	CMP R0,#1000
+	CMP R0,R3
 	BLT loop2
 
 

sumSquareDifference/main.c

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+#include <stdio.h>
+
+int func();
+
+int main() {
+	printf("%d\n",func());
+}

sumSquareDifference/main.s

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+.global func
+.section .text
+
+func:   @ Find the difference between the sum of the squares and the square of the sum, for the first hundred numbers.
+@ (a+b)^2 = a^2 + b^2 + 2ab
+@ (a+b+c)^2 = a^2 + b^2 + c^2 + 2(ab +bc + ca)
+@ Therefore, the difference must be 2(ab + ac + ad .... + bc + bd + be ... + cd + ce .....)
+
+MOV R0,#0
+MOV R2,#1   @ 'a' from the equation above
+MOV R3,#2   @ 'b' from the equation above
+
+mainloop:
+MUL R1,R2,R3  @ 'a' * 'b' - keep in mind we need to do this for all possible 2-number permutations in the sequence
+ADD R0,R0,R1  @Add the result to R0, which will be returned
+
+incr_b:
+ADD R3,R3,#1  @ Increments 'b'
+
+chk_b:
+CMP R3,#100   @ If 'b' is less than or equal to 100, we continue the multiplication
+BLE mainloop
+
+incr_a:
+ADD R2,R2,#1  @ Increments 'a'
+
+new_b:  @This is a way for me to store R2+1 into R3
+ADD R2,R2,#1
+MOV R3,R2
+SUB R2,R2,#1
+
+chk_a:
+CMP R2,#100
+BLT mainloop
+
+
+mul2:
+LSL R0,R0,#1   @Bitwise left shit by 1 - Multiplies by 2
+
+return:
+BX LR
+
+.section .data