architecture yafn {
	registers:
		storage sys_reg[96];

		view ssz = sys_reg[0..32];  														/* stack size */
		view spn = sys_reg[32..64]; 														/* pointer to stack's beginning */
		view err = sys_reg[64..96]; 														/* error register */


	memory:
		/* 0xFFFFFFFF because we use 32-bit integers, so it will just fit */
		range __constants [0x0..0xFFFFFFFF] {
			cell = 8;
			endianess = little-endian;
			granularity = 0;
		}

		range __data [0x0..0xFFFFFFFF] {
			cell = 8;
			endianess = little-endian;
			granularity = 0;
		}

		range __stack [0x0..0xFFFFFFFF] {
			cell = 8;
			endianess = little-endian;
			granularity = 0;
		}


		range __code [0x0..0xFFFFFFFF] {
			cell = 8;
			endianess = little-endian;
			granularity = 0;
		}

	instructions: /* encodings */
		encode __dat field = immediate[32] data;											/* some integer */
		encode __off field = immediate[32] offset;											/* offset in memory */
		encode __lbl field = immediate[32] offset;											/* pointer to instruction */

		encode __reg field = register {
			ssz = 00,
			spn = 01,
			err = 10
		};


	instructions: /* base */
		instruction emp 	= { 0000 0000 };												/* do nothing */
		instruction hlt		= { 0000 0001 };												/* exits program */
		instruction brp		= { 0000 0010 };												/* breakpoint */
		instruction wrt		= { 0000 0011 };												/* outouts int from stack to console */
		instruction srt		= { 0000 0100 };												/* sorts last N elements of stack */


	instructions: /* stack instructions */

		instruction epush	= { 0001 0001 };												/* pushes error register to stack */

		instruction ipush	= { 0001 0010, __dat as dat };									/* pushes integer to stack */
		instruction mpush	= { 0001 0011, __off as off };									/* pushes from mem storage to stack */
		instruction cpush	= { 0001 0100, __off as off };									/* pushes from constants storage to stack */

		/* pop instructions */
		instruction pop		= { 0001 0101 };												/* discards top value from stack */
		instruction dpl		= { 0001 0110 };												/* duplicates last element from stack */
		instruction sav		= { 0001 0111, __off as off };									/* pops data from stack and stores it in memory */
		instruction swp		= { 0001 1000 };												/* swaps top two values */
		instruction svs		= { 0001 1001 };												/* pops data and place in memory to save */

		instruction rnd		= { 0001 1010 };												/* pushes to stack random int */

		instruction smpsh	= { 0001 1011 };												/* gets mem_ptr from stack to push fom mem */
		instruction scpsh	= { 0001 1100 };												/* gets const_ptr from stack to push fom mem */


	/* all operations automatically pops top elements, so it's necessary to use `dpl` */
	instructions: /* arithmetics */
		instruction add		= { 0010 0000 };												/* adds two top values on stack */
		instruction sub		= { 0010 0001 };												/* substracts two top values of stack */
		instruction mul		= { 0010 0010 };												/* multiplies two top values of stack */
		instruction div		= { 0010 0011 };												/* dividies two top values of stack and pushes to
																							   stack result integer division and remainder */
		instruction neg		= { 0010 0100 };												/* negatives top element of stack */

		instruction inc		= { 0010 0101 };												/* increments top element of stack */
		instruction dec		= { 0010 0110 };												/* decrements top element of stack */


	instructions: /* bitwise ops */
		instruction bor		= { 0011 0000 };												/* bitwise or */

		instruction band	= { 0011 0001 };												/* bitwise and */

		instruction and1	= { 0011 0100 };												/* bitwise and of top element and 1 */
		instruction and2	= { 0011 0101 };												/* bitwise and of top element and 2 */
		instruction and3	= { 0011 0110 };												/* bitwise and of top element and 4 */
		instruction and4	= { 0011 0111 };												/* bitwise and of top element and 8 */

		instruction lsh		= { 0011 0010 };												/* left shift */
		instruction lsh1	= { 0011 1000 };												/* shifts top element left on 1 */
		instruction lsh2	= { 0011 1001 };												/* shifts top element left on 2 */

		instruction rsh		= { 0011 0011 };												/* right shift */
		instruction rsh1	= { 0011 1100 };												/* shifts top element right on 1 */
		instruction rsh2	= { 0011 1101 };												/* shifts top element right on 2 */

		instruction bxor	= { 0011 1111 };												/* bitwise xor */

	instructions: /* conditions and jumps */
		instruction cmp		= { 0100 0000 };												/* compares two elements

																							    ---------------------
																							    | state	| pushes	|
																							    ---------------------
																							    | ==	| 001		|
																							    | >=	| 011		|
																							    | <=	| 101		|
																							    | >		| 010		|
																							    | <		| 100		|
																							    ---------------------

																							    So, the first bit for equality,
																							    second one for greatness and
																							    third one for less */

		instruction eq		= { 0100 0001 };												/* pushes 1 if top values equal, else 0 */
		instruction jmp		= { 0100 0100, __lbl as lbl };									/* jumps to instruction */
		instruction jez		= { 0100 0101, __lbl as lbl };									/* jmps to instructions if 0 on stack top */
		instruction jnz		= { 0100 0110, __lbl as lbl };									/* jmps to instructions if on stack top not 0 */
		instruction call	= { 0100 0111, __lbl as lbl };									/* jmps to instructions and pushes current cursor to stack */

		instruction ret		= { 0100 1000 };												/* jps to address at stack top and pops */
		instruction cmp0	= { 0100 1001 };												/* compares with 0 */


	mnemonics: /* formats */
		format plain1 		is "{1}";														/* for numbers */
		format mem_ptr 		is "*{1}";														/* for memory pointers */
		format const_ptr 	is "#{1}";														/* for constants pointers */

	mnemonics: /* base */
		mnemonic emp();
		mnemonic hlt();
		mnemonic brp();
		mnemonic wrt();
		mnemonic srt();

	mnemonics: /* stack instructions */
		mnemonic epush();

		mnemonic push	for ipush(dat) plain1;
		mnemonic push	for cpush(off) const_ptr;
		mnemonic push	for mpush(off) mem_ptr;

		mnemonic pop();
		mnemonic dpl();
		mnemonic sav	for sav(off) mem_ptr;
		mnemonic swp();
		mnemonic sav	for svs();

		mnemonic rnd();

		mnemonic smpsh();
		mnemonic scpsh();


	mnemonics: /* arithmetics instructions */
		mnemonic add();
		mnemonic sub();
		mnemonic mul();
		mnemonic div();

		mnemonic neg();

		mnemonic inc();
		mnemonic dec();


	mnemonics: /* bitwise instructions */
		mnemonic bor();
		mnemonic band();

		mnemonic and1();
		mnemonic and2();
		mnemonic and3();
		mnemonic and4();

		mnemonic lsh();
		mnemonic lsh1();
		mnemonic lsh2();

		mnemonic rsh();
		mnemonic rsh1();
		mnemonic rsh2();

		mnemonic bxor();

	mnemonics: /* conditions */
		mnemonic cmp();
		mnemonic eq();

		mnemonic jmp	for jmp(lbl) plain1;
		mnemonic jez	for jez(lbl) plain1;
		mnemonic jnz	for jnz(lbl) plain1;


		mnemonic call	for call(lbl) plain1;
		mnemonic ret();

		mnemonic cmp0();
}