Included original chipset functionality

Co-authored-by: sigonasr2 <sigonasr2@gmail.com>

main.cpp

@@ -57,6 +57,7 @@ public:
 	std::mt19937 gen; //Standard mersenne_twister_engine seeded with rd()
 	std::uniform_int_distribution<> distrib;
 	std::array<Key,16>keymap{X,K1,K2,K3,Q,W,E,A,S,D,Z,C,K4,R,F,V};
+	bool USE_ORIGINAL_CHIP8_SET=true;
 
 	std::string Display8(int number){
 		std::bitset<8>numb(number);
@@ -207,7 +208,14 @@ public:
 								reg[X]-=reg[Y];
 							}break;
 							case 0x6:{//Shift Right
-								//reg[X]=reg[Y];
+								if (USE_ORIGINAL_CHIP8_SET){
+									/*
+										In the CHIP-8 interpreter for the original COSMAC VIP, this instruction did the following: It put the value of VY into VX, and then shifted the value in VX 1 bit to the right (8XY6) or left (8XYE). VY was not affected, but the flag register VF would be set to the bit that was shifted out.
+
+										However, starting with CHIP-48 and SUPER-CHIP in the early 1990s, these instructions were changed so that they shifted VX in place, and ignored the Y completely.
+									*/
+									reg[X]=reg[Y];
+								}
 								reg[0xF]=reg[X]&0x1;
 								reg[X]>>=1;
 							}break;
@@ -220,12 +228,16 @@ public:
 							}break;
 							case 0xE:{//Shift Left
 								//std::cout<<"Y is: "<<(int)Y<<std::endl;
-								//reg[X]=reg[Y];
-								std::cout<<"Before left shift: "<<(int)reg[X]<<std::endl;
+								if (USE_ORIGINAL_CHIP8_SET){
+									/*
+										In the CHIP-8 interpreter for the original COSMAC VIP, this instruction did the following: It put the value of VY into VX, and then shifted the value in VX 1 bit to the right (8XY6) or left (8XYE). VY was not affected, but the flag register VF would be set to the bit that was shifted out.
+
+										However, starting with CHIP-48 and SUPER-CHIP in the early 1990s, these instructions were changed so that they shifted VX in place, and ignored the Y completely.
+									*/
+									reg[X]=reg[Y];
+								}
 								reg[0xF]=(reg[X]&0x80)>>7;
-								std::cout<<"Register F: "<<(int)reg[0xF]<<std::endl;
 								reg[X]<<=1;
-								std::cout<<"After Left shift: "<<(int)reg[X]<<std::endl;
 							}break;
 						}
 					}break;
@@ -321,11 +333,19 @@ public:
 								for (int i=0;i<=X;i++){
 									memory[index+i]=reg[i];
 								}
+								if (USE_ORIGINAL_CHIP8_SET){
+									/*The original CHIP-8 interpreter for the COSMAC VIP actually incremented the I register while it worked. Each time it stored or loaded one register, it incremented I. After the instruction was finished, I would be set to the new value I + X + 1.*/
+									index+=X+1;
+								}
 							}break;
 							case 0x65:{//Retrieves registers from V0 to VX in memory pointed by index.
 								for (int i=0;i<=X;i++){
 									reg[i]=memory[index+i];
 								}
+								if (USE_ORIGINAL_CHIP8_SET){
+									/*The original CHIP-8 interpreter for the COSMAC VIP actually incremented the I register while it worked. Each time it stored or loaded one register, it incremented I. After the instruction was finished, I would be set to the new value I + X + 1.*/
+									index+=X+1;
+								}
 							}break;
 						}
 					}break;