diff --git a/README.md b/README.md index a3d50fa..e57317c 100644 --- a/README.md +++ b/README.md @@ -62,37 +62,39 @@ ignored. They don't have to be set to 0. ### Opcodes -| Opcode | Name | Function | Notes | -|--------|---------------------------------------------|--------------------------------|----------------------------------| -| `0` | `LDC c` (load constant) | `c -> ACC` | Bits 23-20 of `ACC` are set to 0 | -| `1` | `LDV a` (load value) | ` -> ACC` | | -| `2` | `STV a` (store value) | `ACC -> ` | | -| `3` | `ADD a` | `ACC + -> ACC` | | -| `4` | `AND a` | `ACC and -> ACC` | Bitwise operation | -| `5` | `OR a` | `ACC or -> ACC` | Bitwise operation | -| `6` | `XOR a` | `ACC xor -> ACC` | Bitwise operation | -| `7` | `EQL a` (equal) | `(ACC == ? -1 : 0) -> ACC` | | -| `8` | `JMP a` (jump) | `a -> IAR` | | -| `9` | `JMN a` (jump if negative) | `if (ACC < 0) {a -> IAR}` | | -| `A` | `LDIV a` (load indirect value) | `<> -> ACC` | | -| `B` | `STIV a` (store indirect value) | `ACC -> <>` | | -| `C` | `CALL a` | `IAR -> RA; JMP a` | | -| `D` | `LDVR d` (load value with relative offset) | ` -> ACC` | | -| `E` | `STVR d` (store value with relative offset) | `ACC -> ` | | -| `F0` | `HALT` | Halt execution | | -| `F1` | `NOT` | `not ACC -> ACC` | Bitwise operation | -| `F2` | `RAR` (rotate ACC right) | `ACC >> 1 -> ACC` | See below | -| `F3` | `RET` (return) | `RA -> IAR` | | -| `F4` | `LDSP` (load from SP) | `SP -> ACC` | | -| `F5` | `STSP` (store to SP) | `ACC -> SP` | | -| `F6` | `LDFP` (load from FP) | `FP -> ACC` | | -| `F7` | `STFP` (store to FP) | `ACC -> FP` | | -| `F8` | `LDRA` (load from RA) | `RA -> ACC` | | -| `F9` | `STRA` (store to RA) | `ACC -> RA` | | -| `FA` | `ADC c` (add constant) | `ACC + c -> ACC` | See below | +| Opcode | Name | Function | +|--------|---------------------------------------------|--------------------------------| +| `0` | `LDC c` (load constant) | `c -> ACC` | +| `1` | `LDV a` (load value) | ` -> ACC` | +| `2` | `STV a` (store value) | `ACC -> ` | +| `3` | `ADD a` | `ACC + -> ACC` | +| `4` | `AND a` | `ACC and -> ACC` | +| `5` | `OR a` | `ACC or -> ACC` | +| `6` | `XOR a` | `ACC xor -> ACC` | +| `7` | `EQL a` (equal) | `(ACC == ? -1 : 0) -> ACC` | +| `8` | `JMP a` (jump) | `a -> IAR` | +| `9` | `JMN a` (jump if negative) | `if (ACC < 0) {a -> IAR}` | +| `A` | `LDIV a` (load indirect value) | `<> -> ACC` | +| `B` | `STIV a` (store indirect value) | `ACC -> <>` | +| `C` | `CALL a` | `IAR -> RA; JMP a` | +| `D` | `LDVR d` (load value with relative offset) | ` -> ACC` | +| `E` | `STVR d` (store value with relative offset) | `ACC -> ` | +| `F0` | `HALT` | Halt execution | +| `F1` | `NOT` | `not ACC -> ACC` | +| `F2` | `RAR` (rotate ACC right) | `ACC >> 1 -> ACC` | +| `F3` | `RET` (return) | `RA -> IAR` | +| `F4` | `LDRA` (load from RA) | `RA -> ACC` | +| `F5` | `STRA` (store to RA) | `ACC -> RA` | +| `F6` | `LDSP` (load from SP) | `SP -> ACC` | +| `F7` | `STSP` (store to SP) | `ACC -> SP` | +| `F8` | `LDFP` (load from FP) | `FP -> ACC` | +| `F9` | `STFP` (store to FP) | `ACC -> FP` | +| `FA` | `ADC c` (add constant) | `ACC + c -> ACC` | -- `RAR` shifts all bits in the `ACC` right by one. The rightmost bit wraps around to the leftmost position. -- `ADC c` interprets bits 15-0 as a signed integer, whose value is then added to the `ACC`'s current value. +* `LDC c` sets bits 23-20 of `ACC` to 0. +* `ADD a`, `AND a`, `OR a`, `XOR a` and `NOT` are bitwise operations +* `RAR` shifts all bits in the `ACC` right by one. The rightmost bit wraps around to the leftmost position. +* `ADC c` interprets bits 15-0 as a signed integer, whose value is then added to the `ACC`'s current value. ## File format @@ -118,7 +120,7 @@ The registers and memory are stored as follows: | Word | Content | |--------------:|-------------| -| 0 | `IR` | +| 0 | `IAR` | | 1 | `ACC` | | 2 | `RA` | | 3 | `SP` |