Skip to content

Latest commit

 

History

History
50 lines (45 loc) · 3.96 KB

README.md

File metadata and controls

50 lines (45 loc) · 3.96 KB

chip-8-emulator

A CHIP-8 Emulator in Kotlin Multiplatform targeting the JVM and JS

JVM Kotlin/JS Quality Gate Status Coverage

https://lpicanco.github.io/chip-8-emulator/

Demo

Implemented Opcodes

Instruction Description
00E0 Clears the screen
00EE Returns from a subroutine
1NNN Jumps to address NNN
2NNN Calls subroutine at NNN
3XNN Skips the next instruction if VX equals NN
4XNN Skips the next instruction if VX doesn't equal NN
5XY0 Skips the next instruction if VX equals VY
6XNN Sets VX to NN
7XNN Adds NN to VX without changing the carry flag
8XY0 Sets VX to the value of VY
8XY1 Sets VX to VX OR VY
8XY2 Sets VX to VX AND VY
8XY3 Sets VX to VX XOR VY
8XY4 Adds VY to VX. VF is set to 1 when there's a carry, and to 0 when there isn't
8XY5 VY is subtracted from VX. VF is set to 0 when there's a borrow, and 1 when there isn't
8XY6 Stores the least significant bit of VX in VF and then shifts VX to the right by 1
8XY7 Sets VX to VY minus VX. VF is set to 0 when there's a borrow, and 1 when there isn't
8XYE Stores the most significant bit of VX in VF and then shifts VX to the left by 1
9XY0 Skips the next instruction if VX doesn't equal VY
ANNN Sets I to the address NNN
BNNN Jumps to the address NNN plus V0
CXNN Sets VX to the result of a bitwise and operation on a random number (Typically: 0 to 255) and NN
DXYN Draws a sprite at coordinate (VX, VY) that has a width of 8 pixels and a height of N+1 pixels. Each row of 8 pixels is read as bit-coded starting from memory location I; I value doesn’t change after the execution of this instruction. As described above, VF is set to 1 if any screen pixels are flipped from set to unset when the sprite is drawn, and to 0 if that doesn't happen
EX9E Skips the next instruction if the key stored in VX is pressed
EXA1 Skips the next instruction if the key stored in VX isn't pressed
FX07 Sets VX to the value of the delay timer
FX0A A key press is awaited, and then stored in VX. (Blocking Operation. All instruction halted until next key event)
FX15 Sets the delay timer to VX
FX18 Sets the sound timer to VX
FX1E Adds VX to I. VF is not affected
FX29 Sets I to the location of the sprite for the character in VX. Characters 0-F (in hexadecimal) are represented by a 4x5 font
FX33 Stores the binary-coded decimal representation of VX, with the most significant of three digits at the address in I, the middle digit at I plus 1, and the least significant digit at I plus 2
FX55 Stores V0 to VX (including VX) in memory starting at address I. The offset from I is increased by 1 for each value written, but I itself is left unmodified
FX65 Fills V0 to VX (including VX) with values from memory starting at address I. The offset from I is increased by 1 for each value written, but I itself is left unmodified