Finished assembler and documented

Author: Mekapaedia

README.md

@@ -1,2 +1,94 @@
 # CPU Assembler
-The assembler for the Nibble Knowledge CPU
+The assembler for the Nibble Knowledge CPU.
+
+AS4
+---
+
+AS4 is the low level assembler on written in C99 for the Nibble Knowledge CPU. It is under 700 lines of executable code, and recognises only 12 contructs:
+
+### 8 instructions ###
+The Nibble Knowledge CPU has 8 instructions which are split into two different types:
+* Solitary instructions that do not require a memory address (has the format INST)
+	* NOP: No operation
+	* HLT: Halt CPU
+	* CXA: Copy the carry bit (soon to be overflow bit?) and the XOR of that bit and the MSB of the accumulator.
+* Binary instructions that require a memory address (has the formal INST ADDR)
+	* ADD: Add the nibble at the specified memory address to the accumulator.
+	* NND: NAND the nibble at the specified memory address to the accumulator.
+	* JMP: Jump to the specified memory address if the accumulator is 0.
+	* LOD: Load the accumulator with the nibble at the specified address.
+	* STR: Store the nibble in the accumulator to the specified memory address.
+
+### 2 data types ###
+AS4 recognises two inbuilt data types:
+* Numberical values. Format: ".data SIZE INITIAL VALUE"
+* Strings, both plain and zero terminated. Format: ".ascii "String"" or ".asciiz "String""
+	* Strings must start and end with double quotes.
+	* AS4 recognises standard escape characters
+
+### Labels ###
+Labels are of the format "NAME:". They are used to refer to memory locations without having to memorise or calculate number.
+An example of useage would be "number: .data 1 2", which is using the label "number" to point to a data element of 1 nibble in size with the initial value of 2.
+
+### Comments ###
+Comments in AS4 start with a semicolon, ";".
+
+### Example code ###
+; This program reads in integers and adds them together
+; until a negative number is read in.  Then it outputs
+; the sum (not including the last number).
+
+;Start:	read		; read n -> acc
+;	jmpn  Done  	; jump to Done if n < 0.
+;	add   sum  	; add sum to the acc
+;	store sum 	; store the new sum
+;	jump  Start	; go back & read in next number
+;Done:	load  sum 	; load the final sum
+;	write 		; write the final sum
+;	stop  		; stop
+;
+;sum:	.data 2 0 ; 2-byte location where sum is stored
+
+;; START NIbble-Knowledge code ;;
+
+;; Instruction Section ;;
+
+Start: 
+	LOD n15
+	ADD n2
+	NND n15
+	NOP
+	CXA 
+	JMP Jump
+	STR sum
+	
+Jump:	HLT 
+
+
+;; Data Section ;;
+n0: .data  1 0  ; b0000
+n1: .data  1 1  ; b0001
+n2: .data  1 2  ; b0010
+n3: .data  1 3  ; b0011
+n4: .data  1 4  ; b0100
+n5: .data  1 5  ; b0101
+n6: .data  1 6  ; b0110
+n7: .data  1 7  ; b0111
+n8: .data  1 8  ; b1000
+n9: .data  1 9  ; b1001
+n10: .data 1 10 ; b1010
+n11: .data 1 11 ; b1011
+n12: .data 1 12 ; b1100
+n13: .data 1 13 ; b1101
+n14: .data 1 14 ; b1110
+n15: .data 1 15 ; b1111
+
+derp: .data 6 0x454534
+
+derp3: .ascii "hey there"
+derp4: .ascii "hey\" there\n"
+derp5: .asciiz "hey there"
+derp6: .asciiz "hey\" there\n"
+
+sum: .data 1 0
+

TestCodeNibbleV2.asm

@@ -16,6 +16,7 @@
 ;; START NIbble-Knowledge code ;;
 
 ;; Instruction Section ;;
+
 Start: 
 	LOD n15
 	ADD n2
@@ -46,6 +47,15 @@ n13: .data 1 13 ; b1101
 n14: .data 1 14 ; b1110
 n15: .data 1 15 ; b1111
 
+derp: .data 6 0x454534
+
+derp3: .ascii "hey there"
+derp4: .ascii "hey\" there\n"
+derp5: .asciiz "hey there"
+derp6: .asciiz "hey\" there\n"
+
 sum: .data 1 0
 
 
+
+