; RETURN and CALL are built-in assembler macros, not actual instructions

SYMBOL		SIEVE_SIZE		62
SYMBOL		SIEVE_WORDS		32

SYMBOL		TO_SIEVE		33
SYMBOL		V_I			34
SYMBOL		V_I2			35
SYMBOL		RET			36
SYMBOL		TEMP			37
SYMBOL		ZERO			38

MAIN
	LDI			0
	STA			V_I
	STB			ZERO
FILL_LOOP
	LDI			0
	LDM			V_I
	LDM
	STA
	LDI			1
	qADD			V_I
	STB
	LDI			SIEVE_WORDS
	qEQL			V_I
	JZ			FILL_LOOP
	
	LDI			3
	STA			V_I
	LDI			0
	STA			V_I2
SIEVE_LOOP
	CALL			IS_IN_SIVE
	LDI			0
	qEQL			RET
	JZ			NOT_PRIME
	
	LDA			V_I
	STA			63
	CALL			MARK_MULTIPLES
	
NOT_PRIME
	LDI			2
	qADD			V_I
	STB
	LDI			1
	qADD			V_I2
	STB
	LDI			SIEVE_SIZE
	qMAG			V_I
	JNZ			SIEVE_LOOP
	
HALT
	NOP
	NOP
	NOP
	NOP
	NOP
	NOP
	NOP
	NOP
	NOP
	NOP
	JMP			HALT
	
IS_IN_SIVE
	LDM			V_I2
	LDM
	LDA
	STA			RET
	RETURN
	
MARK_MULTIPLES
	LDA			V_I2
	STA			TEMP
MARK_LOOP
	LDI			1				// sieve[i] = 1
	LDM			TEMP
	LDM
	STA
	
	LDA			V_I
	qADD			TEMP
	STB
	LDI			0				// Integer overflow exit condition
	qADC			ZERO
	JNZ			MARK_LOOP_END
	LDI			SIEVE_WORDS		// i > size size exit condition
	qMAG			TEMP
	JNZ			MARK_LOOP

MARK_LOOP_END
	RETURN