Initial Commit with everything done

Project 4/Fill.asm

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+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/04/Fill.asm
+
+// Runs an infinite loop that listens to the keyboard input.
+// When a key is pressed (any key), the program blackens the screen,
+// i.e. writes "black" in every pixel;
+// the screen should remain fully black as long as the key is pressed. 
+// When no key is pressed, the program clears the screen, i.e. writes
+// "white" in every pixel;
+// the screen should remain fully clear as long as no key is pressed.
+
+// Put your code here.
+(LOOP)
+    @R1
+    M=0
+    @KBD
+    D=M
+    @BLACK
+    D;JGT
+    @WHITE
+    D;JEQ
+(BLACK)
+    @SCREEN
+    D=M
+    @LOOP
+    D;JLT
+    (BLACKLOOP)
+    @R1
+    D=M
+    M=M+1
+    @SCREEN
+    AD=D+A
+    M=-1
+    @24575
+    D=D-A
+    @LOOP
+    D;JEQ
+    @BLACKLOOP
+    0;JMP
+(WHITE)
+    @SCREEN
+    D=M
+    @LOOP
+    D;JEQ
+    (WHITELOOP)
+    @R1
+    D=M
+    M=M+1
+    @SCREEN
+    AD=D+A
+    M=0
+    @24575
+    D=D-A
+    @LOOP
+    D;JEQ
+    @WHITELOOP
+    0;JMP

Project 4/Mult.asm

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+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/04/Mult.asm
+
+// Multiplies R0 and R1 and stores the result in R2.
+// (R0, R1, R2 refer to RAM[0], RAM[1], and RAM[2], respectively.)
+
+// Put your code here.
+    @R2
+    M=0
+(LOOP)
+    @R0
+    D=M
+    @END
+    D;JLE
+    @R0
+    M=M-1
+    @R1
+    D=M
+    @R2
+    M=D+M
+    @LOOP
+    0;JMP
+(END)
+    @END