Super-chip
Information
The Super-chip interpreter for the modified VIP (chip10 modification) and Studio IV was designed by me. It should support Super-CHIP 1.1, 00FA instruction from chip8run and also somewhat follows SCHIP/SCHPC however with some selectable options/quirks:
- SHIFT: When selected Vy will be ignored for SHL/SHR Vx, Vy instructions
- LOAD: When selected I will NOT be incremented for LD VX,[I] and LD [i], Vx
- BXNN: When selected JP B,aaa will jump to address xaa + V0 instead of aaa + V0
- VBLNK: When selected interpreter will wait for VBLaNK before drawing a sprite
- CLIPS: When selected Sprites will be CLIPed at top/bottom of screen
Note depending on keypad mapping 4 and 5 might be mapped to PC keys Q and W. To start the chip8 or Super-chip game press any key other than 1 to 5.
For chip8 games use: SHIFT, LOAD, BXNN not selected, VBLNK, CLIPS selected
For most Super-chip games use: SHIFT, LOAD, BXNN selected, VBLNK, CLIPS not selected
Some Super-chip games need the following setting:
- Chipcross: SHIFT selected, LOAD not selected, BNNN selected, VBLNK & CLIPS not selected
- Eaty the Alien: No options selected
- Grad School Simulator: No options selected
- Codegrid: No options selected
- Mr. Worm: No options selected
- Octopeg: No options selected
- Sub-Terr8nia: No options selected
Super-chip code should be located from 800-17FF. Note that address 800 is seen as 200 by the interpreter. So a command 2200 will do a call to address 800 instead of 200. Video memory is located from 1C00 to 1FFF and Vx-Vy are stored from 1BF0 to 1BFF.
Definitions
| aaa | 12 bit address |
| kk | 8 bit constant |
| x | Register number Vx (x = 0 to F) |
| y | Register number Vy (y = 0 to F) |
| [aaa] | Memory value of address aaa |
| . | Not used, value doesn't matter |
| 1..9, A..F | Hexadecimal digits |
Syntax
| Opcode | Mnemonic | Parameter | Definition |
|---|---|---|---|
| Fx1E | ADD | I, Vx | I = I + Vx |
| 7xkk | ADD | Vx, kk | Vx = Vx + kk |
| 8xy4 | ADD | Vx, Vy | Vx = Vx + Vy, VF = carry |
| 8xy2 | AND | Vx, Vy | Vx = Vx AND Vy, VF undefined |
| 2aaa | CALL | aaa | Call subroutine at aaa (16 levels) |
| 00E0 | CLS | Clear display | |
| 00FA | COMP | Set compatibility mode for FX55 and FX65; running this changes the behaviour of those instructions so they no longer change I | |
| Dxyn | DRW | Vx, Vy, n | Draw n byte sprite stored at [I] at Vx, Vy. Set VF = collision If n=0 a 16x16 sprite is drawn in high res mode and a 8x16 sprite in low res mode |
| 00FF | HIGH | High-resolution mode | |
| 1aaa | JP | aaa | Jump to address aaa |
| Baaa | JP | V0, aaa | BXNN option NOT selected: Jump to address aaa + V0 BXNN option selected: Jump to address xaa + V0 |
| Fx33 | LD | B, Vx | Store BCD value of Vx in [I], [I+1], [I+2] |
| Fx15 | LD | DT, Vx | Delaytimer = Vx |
| Fx29 | LD | F1, Vx | Point I to 5 byte numeric sprite for value in Vx |
| Fx29 | LD | F2, Vx | Point I to 10 byte numeric sprite for value in Vx |
| Aaaa | LD | I, aaa | I = aaa |
| Fx18 | LD | ST, Vx | Soundtimer = Vx |
| Fx07 | LD | Vx, DT | Vx = Delaytimer |
| Fx0A | LD | Vx, K | Vx = key, wait for keypress |
| 6xkk | LD | Vx, kk | Vx = kk |
| 8xy0 | LD | Vx, Vy | Vx = Vy, VF undefined |
| Fx65 | LD | Vx, [I] | Read V0 .. Vx from [I] .. [I+x] LOAD option NOT selected: register I will be incremented LOAD option selected: register I will not be incremented |
| Fx55 | LD | [I], Vx | Store V0 .. Vx in [I] .. [I+x] LOAD option NOT selected: register I will be incremented LOAD option selected: register I will not be incremented |
| 00FE | LOW | Low-resolution mode | |
| 00FD | NOP | No operation, for backward compatibility to the Super-Chip 1.0 Exit interpreter command | |
| 8xy1 | OR | Vx, Vy | Vx = Vx OR Vy, VF undefined |
| Fx85 | READ | Read V0..VX from RPL user flags (X <= 7), RPL is stored on 1BE0-1BE7 | |
| 00EE | RETURN | Return from subroutine (16 levels) | |
| Cxkk | RND | Vx , kk | Vx = random AND kk |
| 00CN | SCD | Scroll display N pixels down; in low resolution mode, N/2 pixels | |
| 00FC | SCL | Scroll left by 4 pixels; in low resolution mode, 2 pixels | |
| 00FB | SCR | Scroll right by 4 pixels; in low resolution mode, 2 pixels | |
| 3xkk | SE | Vx , kk | Skip next instruction if Vx == kk |
| 5xy0 | SE | Vx , Vy | Skip next instruction if Vx == Vy |
| 8xxE | SHL | Vx | Vx = Vx << 1, VF = carry |
| 8xyE | SHL | Vx , Vy | SHIFT option NOT selected: Vx = Vy << 1, VF = carry SHIFT option selected: Vx = Vx << 1, VF = carry |
| 8xx6 | SHR | Vx | Vx = Vx >> 1, VF = carry |
| 8xy6 | SHR | Vx , Vy | SHIFT option NOT selected: Vx = Vy >> 1, VF = carry SHIFT option selected: Vx = Vx >> 1, VF = carry |
| Ex9E | SKP | Vx | Skip next instruction if key Vx down |
| ExA1 | SKNP | Vx | Skip next instruction if key Vx up |
| 4xkk | SNE | Vx, kk | Skip next instruction if Vx != kk |
| 9xy0 | SNE | Vx, Vy | Skip next instruction if Vx != Vy |
| Fx75 | STORE | Store V0..VX in RPL user flags (X <= 7), RPL is stored on 1BE0-1BE7 | |
| 8xy5 | SUB | Vx, Vy | Vx = Vx - Vy, VF = !borrow |
| 8xy7 | SUBN | Vx, Vy | Vx = Vy - Vx, VF = !borrow |
| 0aaa | SYS | aaa | Call CDP1802 code at aaa |
| 8xy3 | XOR | Vx, Vy | Vx = Vx XOR Vy, VF undefined |