#include "decoderImp.h"

/*void decodeInstructionImp(proc_t *proc, opcode_t *op, opcode_data_t *instruction, char rule) {
	int args=0;
	switch(rule) {
		case RULE_1:
		case RULE_1d:
//		case RULE_1s:
			args=1;
			break;
		case RULE_2:
		case RULE_2d:
		case RULE_2s:
			args=2;
	}
	instruction->argc=args;
	if(rule==RULE_2s) {
		//pass the first argument as it
		instruction->arg0.i=op->arg0;
		Stack_pop(&proc->stack, &instruction->args[1]);
	} else if(op->nArgs==0) {
		//pop the arguments from stack
		for(int i=0; i<args; i++) {
			Stack_pop(&proc->stack, &instruction->args[i]);
		}
	} else if(op->nArgs==3&&args!=0) {
		//decode the immediate value
		if(rule==RULE_1d||rule==RULE_2d) {
			//immediate decimal
			instruction->arg0.d=(decimal_t) ((((op->imm>>15)&1)?-1:1)*((op->imm>>4)&0x7ff)<<(op->imm&0xf));
		} else {
			//immediate signed integral
			instruction->arg0.i=(integral_t) op->imm;
		}
		//if we have another argument, pop it
		if(args==2) {
			Stack_pop(&proc->stack, &instruction->args[1]);
		}
	} else {
		//all arguments are from registers
		for(int i=0; i<args; i++) {
			instruction->args[i]=proc->registers[op->args[i]];
		}
	}
}*/
void decodeInstructionImp(proc_t *proc, opcode_t *op, opcode_data_t *instruction, char rule) {
	//get the number of arguments
	int args=0;
	switch(rule) {
		case RULE_1:
		case RULE_1d:
//		case RULE_1s:
			args=1;
			break;
		case RULE_2:
		case RULE_2d:
		case RULE_2s:
			args=2;
	}
	instruction->argc=args;
	
	if(args==0) {
		//do nothing
		return;
	} else if(args==1) {
		//read a single argument
		if(op->nArgs==3) {
			//read immediate argument
			if(rule==RULE_1d||rule==RULE_2d) {
				//immediate decimal
				instruction->arg0.d=(decimal_t) ((((op->imm>>15)&1)?-1:1)*((op->imm>>4)&0x7ff)<<(op->imm&0xf));
			} else {
				//immediate signed integral
				instruction->arg0.i=(integral_t) op->imm;
			}
			return;
		} else if(op->nArgs==0) {
			//pop from stack
			Stack_pop(&proc->stack, &instruction->arg0);
			return;
		} else { //op->nArgs==1||op->nArgs==2
			//read from registers
			if(rule==RULE_2s) {
				//or, in this case, we don't
				instruction->arg0.i=op->arg0;
			} else {
				instruction->arg0=proc->registers[op->arg0%256];
			}
			return;
		}
	} else { //args==2
		if(op->nArgs==3) {
			//read immediate argument
			if(rule==RULE_1d||rule==RULE_2d) {
				//immediate decimal
				instruction->arg0.d=(decimal_t) ((((op->imm>>15)&1)?-1:1)*((op->imm>>4)&0x7ff)<<(op->imm&0xf));
			} else {
				//immediate signed integral
				instruction->arg0.i=(integral_t) op->imm;
			}
			//pop the other one from the stack
			Stack_pop(&proc->stack, &instruction->arg1);
			return;
		} else if(op->nArgs==0) {
			//pop from stack
			Stack_pop(&proc->stack, &instruction->arg0);
			Stack_pop(&proc->stack, &instruction->arg1);
			return;
		} else { //op->nArgs==1||op->nArgs==2
			//read from the first register
			if(rule==RULE_2s) {
				//or, in this case, we don't
				instruction->arg0.i=op->arg0;
			} else {
				instruction->arg0=proc->registers[op->arg0%256];
			}
			
			if(op->nArgs==2) {
				//read from the second register
				instruction->arg1=proc->registers[op->arg1%256];
			} else {
				//pop the second argument from the stack
				Stack_pop(&proc->stack, &instruction->arg1);
			}
			return;
		}
	}
}

/*void decodeInstructionExtImp(proc_t *proc, opcode_ext_t *op, opcode_data_t *instruction, char rule) {
	int args=0;
	switch(rule) {
		case RULE_1:
		case RULE_1d:
//		case RULE_1s:
			args=1;
			break;
		case RULE_2:
		case RULE_2d:
		case RULE_2s:
			args=2;
	}
	instruction->argc=args;
	if(rule==RULE_2s) {
		//pass the first argument as it
		instruction->arg0.i=op->arg0;
		Stack_pop(&proc->stack, &instruction->args[1]);
	} else if(op->nArgs==0) {
		//pop the arguments from stack
		for(int i=0; i<args; i++) {
			Stack_pop(&proc->stack, &instruction->args[i]);
		}
	} else if(op->nArgs==3&&args!=0) {
		//decode the immediate value
		if(rule==RULE_1d||rule==RULE_2d) {
			//immediate decimal
			instruction->arg0.d=(decimal_t) ((((op->imm>>15)&1)?-1:1)*((op->imm>>4)&0x7ff)<<(op->imm&0xf));
		} else {
			//immediate signed integral
			instruction->arg0.i=(integral_t) op->imm;
		}
		//if we have another argument, pop it
		if(args==2) {
			Stack_pop(&proc->stack, &instruction->args[1]);
		}
	} else {
		//all arguments are from registers
		for(int i=0; i<args; i++) {
			instruction->args[i]=proc->registers[op->args[i]];
		}
	}
}*/

void decodeInstructionExtImp(proc_t *proc, opcode_ext_t *op, opcode_data_t *instruction, char rule) {
	//get the number of arguments
	int args=0;
	switch(rule) {
		case RULE_1:
		case RULE_1d:
//		case RULE_1s:
			args=1;
			break;
		case RULE_2:
		case RULE_2d:
		case RULE_2s:
			args=2;
	}
	instruction->argc=args;
	
	if(args==0) {
		//do nothing
		return;
	} else if(args==1) {
		//read a single argument
		if(op->nArgs==3) {
			//read immediate argument
			if(rule==RULE_1d||rule==RULE_2d) {
				//immediate decimal
				instruction->arg0.d=(decimal_t) ((((op->imm>>15)&1)?-1:1)*((op->imm>>4)&0x7ff)<<(op->imm&0xf));
			} else {
				//immediate signed integral
				instruction->arg0.i=(integral_t) op->imm;
			}
			return;
		} else if(op->nArgs==0) {
			//pop from stack
			Stack_pop(&proc->stack, &instruction->arg0);
			return;
		} else { //op->nArgs==1||op->nArgs==2
			//read from registers
			if(rule==RULE_2s) {
				//or, in this case, we don't
				instruction->arg0.i=op->arg0;
			} else {
				instruction->arg0=proc->registers[op->arg0%256];
			}
			return;
		}
	} else { //args==2
		if(op->nArgs==3) {
			//read immediate argument
			if(rule==RULE_1d||rule==RULE_2d) {
				//immediate decimal
				instruction->arg0.d=(decimal_t) ((((op->imm>>15)&1)?-1:1)*((op->imm>>4)&0x7ff)<<(op->imm&0xf));
			} else {
				//immediate signed integral
				instruction->arg0.i=(integral_t) op->imm;
			}
			//pop the other one from the stack
			Stack_pop(&proc->stack, &instruction->arg1);
			return;
		} else if(op->nArgs==0) {
			//pop from stack
			Stack_pop(&proc->stack, &instruction->arg0);
			Stack_pop(&proc->stack, &instruction->arg1);
			return;
		} else { //op->nArgs==1||op->nArgs==2
			//read from the first register
			if(rule==RULE_2s) {
				//or, in this case, we don't
				instruction->arg0.i=op->arg0;
			} else {
				instruction->arg0=proc->registers[op->arg0%256];
			}
			
			if(op->nArgs==2) {
				//read from the second register
				instruction->arg1=proc->registers[op->arg1%256];
			} else {
				//pop the second argument from the stack
				Stack_pop(&proc->stack, &instruction->arg1);
			}
			return;
		}
	}
}