initial commit

.gitignore

@@ -0,0 +1,10 @@
+# ASM object files
+*.o
+
+# Executables
+tictactoe/tictactoe
+tutorial/branching
+tutorial/conditionaljump
+tutorial/helloworld
+tutorial/inputexample
+tutorial/instructions

armv6/tictactoe/makefile

@@ -0,0 +1,13 @@
+AS = as
+LD = ld
+
+%.o: %.s
+	$(AS) $^ -o $@
+
+tictactoe: tictactoe.o
+	$(LD) $^ -o $@
+
+.PHONY: clean
+clean:
+	rm tictactoe
+	rm *.o

armv6/tictactoe/tictactoe.s

@@ -0,0 +1,195 @@
+.global _start
+
+_start:
+	BL	_printboard
+_inputloop:
+	BL	_getdigit
+	LDR	R1, =firstmove
+	STRB	R0, [R1]
+	BL	_getdigit
+	LDR 	R2, =firstmove
+	LDRB	R1, [R2]
+	BL	_isvalidmove
+	CMP	R2, #1
+	BEQ	_inputloop		@ move was invalid, retry
+
+	BL	_checkwin		@ check if move was a winning one
+	CMP	R0, #1
+	BEQ	_player_won
+
+	LDR	R1, =currentmove	@ check if max moves exceeded
+	LDRB	R2, [R1]
+	ADD	R0, R2, #1
+	CMP	R0, #8
+	BHI	_tie_end		@ max moves achieved, its a tie
+	STRB	R0, [R1]
+
+	LDR	R1, =currentplayer	@ change active player
+	LDRB	R0, [R1]
+	CMP	R0, #79			@ '79' == 'O', player 1
+	BEQ	_setplayer2
+	MOV	R0, #79			@ set current player to 1
+	STRB	R0, [R1]
+	B	_start
+_setplayer2:
+	MOV	R0, #88			@ set current player to 2
+	STRB	R0, [R1]
+	B	_start
+
+_player_won:
+	LDR	R1, =currentplayer
+	LDRB	R0, [R1]
+	LDR	R1, =output_player_won
+	ADD	R2, R1, #7
+	STRB	R0, [R2]		@ store the current player as winner
+	MOV	R2, #14
+	BL	_print
+	B	_end
+_tie_end:
+	LDR	R1, =output_tie
+	MOV	R2, #5
+	BL	_print
+_end:
+	BL	_printboard
+	MOV	R7, #1
+	SWI	0
+
+_checkwin:
+	MOV	R0, #0
+_checkwin_iterate:
+	LDR	R2, =boardlines	@ base ptr
+	LDR	R3, =board
+	ADD	R1, R2, R0	@ iteration offset
+
+	LDRB	R2, [R1], #1	@ index to check
+	ADD	R4, R2, R3
+	LDRB	R5, [R4]	@ cell #1
+	CMP	R5, #95		@ stop if first cell is empty
+	BEQ	_checkwin_next_line
+
+	LDRB	R2, [R1], #1
+	ADD	R4, R2, R3
+	LDRB	R6, [R4]	@ cell #2
+	CMP	R5, R6
+	BNE	_checkwin_next_line
+
+	LDRB	R2, [R1]
+	ADD	R4, R2, R3
+	LDRB	R7, [R4]	@ cell #3
+	CMP	R5, R7
+	BNE	_checkwin_next_line
+	B	_checkwin_win
+
+_checkwin_next_line:
+	ADD	R1, R0, #3
+	MOV	R0, R1
+	CMP	R0, #21
+	BLS	_checkwin_iterate
+_checkwin_nowin:
+	MOV	R0, #0
+	BX	lr
+_checkwin_win:
+	MOV	R0, #1
+	BX	lr
+
+_isvalidmove:	@ checks if the move in R0, R1 is valid and sets R2 accordingly
+	MOV	R3, #3
+	MUL	R2, R1, R3
+	ADD	R3, R0, R2
+	LDR	R4, =board
+	ADD 	R2, R4, R3
+	LDRB	R3, [R2]
+	CMP	R3, #95			@ '95' == _ character, empty cell
+	BEQ	_isvalidmove_succ
+	MOV 	R2, #1			@ error, cell already set, retry!
+	BX	lr
+_isvalidmove_succ:
+	LDR	R3, =currentplayer	@ store the move in the board
+	LDRB	R4, [R3]
+	STRB	R4, [R2]
+	MOV 	R2, #0			@ cell set
+	BX	lr
+
+_getdigit:	@ Puts the first read char in R0
+	MOV 	R3, lr		@ backup lr ptr
+_getinput:
+	LDR 	R1, =inputreq
+	MOV 	R2, #6
+	BL 	_print
+	MOV	R7, #3		@ syscall read
+	MOV	R0, #0		@ from kb device
+	MOV	R2, #2
+	LDR	R1, =input	@ into
+	SWI	0		@ interrupt to let sys handle the call
+	LDR	R1, =input
+	LDRB	R2, [R1]
+	CMP	R2, #48		@ ascii value of '0'
+	BLS	_getinput
+	CMP	R2, #51		@ ascii value of '3'
+	BHI	_getinput
+	SUB	R0, R2, #49	@ subtract ascii value of '1' to bring result into range 0 to 2
+	MOV	lr, R3		@ restore lr ptr
+	BX	lr		@ Return
+
+_printboard:
+	MOV	R10, lr
+	MOV	R4, #0		@ row index (0, 3 or 6)
+_printboard_row:
+	MOV	R3, #0		@ value index (0, 1, 2)
+_printboard_nextvalue:
+	ADD	R1, R3, R4	@ calculate index
+	LDR	R0, =board
+	ADD	R2, R0, R1	@ get board array ptr
+	LDRB	R0, [R2]	@ load board byte
+	LDR	R1, =output_row
+	ADD	R2, R1, R3	@ get row output str ptr
+	STRB	R0, [R2]	@ store the player char in output str
+
+	ADD	R0, R3, #1		@ up the value counter
+	MOV	R3, R0
+	CMP	R3, #2			@ check if we should print the row
+	BLS	_printboard_nextvalue	@ no, still 1 or more values to insert
+
+	LDR	R1, =output_row		@ prepare to print the row
+	MOV	R2, #4
+	BL	_print			@ print the row
+
+	ADD	R5, R4, #3		@ get next row
+	MOV	R4, R5
+	CMP	R4, #6			@ check if not on last row already
+	BHI	_printboard_end		@ printed all 3 rows, quit
+	B	_printboard_row
+_printboard_end:
+	BX	R10
+
+_print:		@ prints the message pointed at by R1 with size in R2
+	MOV R7, #4	@ syscall write
+	MOV R0, #1	@ to the screen
+	SWI 0
+	BX lr
+
+.data
+currentplayer:
+	.byte 79
+currentmove:
+	.byte 0x00
+.align 9
+board:
+	.byte 95, 95, 95, 95, 95, 95, 95, 95, 95
+.align 24
+boardlines:
+	.byte 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 3, 6, 1, 4, 7, 2, 5, 8, 0, 4, 8, 6, 4, 2	 @ 8 x 3
+firstmove:
+	.byte 0x00
+endline:
+	.ascii "\n"
+inputreq:
+	.ascii "Input:"			@6
+input:
+	.ascii "  "
+output_row:
+	.ascii "   \n"			@4
+output_tie:
+	.ascii "tie!\n"			@5
+output_player_won:
+	.ascii "player X won!\n"	@ size 14, X at index 7

armv6/tutorial/branching.s

@@ -0,0 +1,12 @@
+@ <intstruction> <destination> , <operand>, <operand>
+
+.global _start
+
+_start:
+	MOV R0, #20
+	B other
+	MOV R0, #11
+
+other:
+	MOV R7, #1
+	SWI 0

armv6/tutorial/conditionaljump.s

@@ -0,0 +1,32 @@
+@ <intstruction> <destination> , <operand>, <operand>
+
+.global _start
+
+/*
+	CMP R1. R2
+	if R1 <  R2 then N is enabled
+	if R1 >  R2 then N is disabled 
+	if R1 == R2 then Z is enabled
+*/
+
+_start:
+	MOV R1, #20
+	MOV R2, #10
+	CMP R1, R2
+	BEQ values_equal
+	BGT values_greater
+
+values_less:
+	MOV R0, #2
+	B end	
+
+values_equal:
+	MOV R0, #1
+	B end
+
+values_greater:
+	MOV R0, #3
+
+end:
+	MOV R7,	#1	@ exit to terminal
+	SWI 0		@ system reads R7 after interrupt

armv6/tutorial/helloworld.s

@@ -0,0 +1,16 @@
+.global _start
+
+_start:
+	MOV R7, #4 @ system call to say we want to output
+	MOV R0, #1 @ use the window as output device
+	MOV R2, #12 @ length of our output message
+	LDR R1, =message
+	SWI 0
+
+end:
+	MOV R7, #1
+	SWI 0
+
+.data
+message:
+	.ascii "Hello World\n"

armv6/tutorial/inputexample.s

@@ -0,0 +1,23 @@
+.global _start
+
+_start:
+	MOV R7, #3	@ system call to say we want to read input
+	MOV R0, #0	@ read from input device keyboard
+	MOV R2, #10	@ read 10 chars
+	LDR R1, =message
+	SWI 0
+
+_write:
+	MOV R7, #4 	@ output
+	MOV R0, #1 	@ to screen
+	MOV R2, #5 	@ 5 chars
+	LDR R1, =message
+	SWI 0
+
+end:
+	MOV R7, #1
+	SWI 0
+
+.data
+message:
+	.ascii " "

armv6/tutorial/instructions.s

@@ -0,0 +1,14 @@
+@ <intstruction> <destination> , <operand>, <operand>
+
+.global _start
+
+_start:
+	MOV R1, #0x04
+	MOV R2, #0x03
+	MOV R3, #0x08
+	ADD R0, R1, R1
+	SUB R0, R1, #0x02
+	MUL R0, R1, R2
+	MLA R0, R1, R2, R3
+	MOV R7, #1
+	SWI 0

armv6/tutorial/logicaloperators.s

@@ -0,0 +1,11 @@
+@ instruction <destination>, <operand>, <operand>
+
+.global _start
+
+_start:
+	MOV R1, #5 @ 0101
+	MOV R2, #9 @ 1001
+	AND R0, R1, R2
+end:
+	MOV R7, #1
+	SWI 0

armv6/tutorial/makefile

@@ -0,0 +1,34 @@
+AS = as
+LINKER = ld
+
+%.o: %.s
+	$(AS) $^ -o $@
+
+tutorial: tutorial.o
+	$(LINKER) $^ -o $@
+
+tutorial2: tutorial2.o tutorial2p2.o
+	$(LINKER) $^ -o $@
+
+helloworld: helloworld.o
+	$(LINKER) $^ -o $@
+
+inputexample: inputexample.o
+	$(LINKER) $^ -o $@
+
+instructions: instructions.o
+	$(LINKER) $^ -o $@
+
+branching: branching.o
+	$(LINKER) $^ -o $@
+
+conditionaljump: conditionaljump.o
+	$(LINKER) $^ -o $@
+
+.PHONY: clean
+clean:
+	rm *.o
+	rm tutorial
+	rm tutorial2
+	rm helloworld
+	rm inputexample

armv6/tutorial/tutorial.s

@@ -0,0 +1,15 @@
+@single line comment
+
+/*
+Multi line comment
+*/
+
+.text
+
+.global _start @entry point
+
+_start: @label
+	MOV R0, #65
+	MOV R7, #1
+
+SWI 0

armv6/tutorial/tutorial2.s

@@ -0,0 +1,4 @@
+.global _start
+_start:
+	MOV R0, #65
+	BAL _part2

armv6/tutorial/tutorial2p2.s

@@ -0,0 +1,4 @@
+.global _part2
+_part2:
+	MOV R7, #1
+	SWI 0

armv6/tutorial/tutorial3.s

@@ -0,0 +1,22 @@
+/*
+bit = 1 bit
+nibble = 4 bits
+byte = 8 bits
+word = 32 bits
+*/
+
+/*
+16 registers of length word
+	13 general purpose
+	1 stack pointer
+	1 link register
+	1 program counter
+*/
+
+/*
+CPSR = Current Program Status Registers
+	N = negative result flag
+	Z = zero result flag
+	C = carry over flag
+	V = overflow flag
+*/