Start on instruction definition

Author: commonkestrel

README.md

@@ -9,10 +9,87 @@ Fateful can be installed through [cargo](https://github.com/rust-lang/cargo) via
 
 The assembler can be used with the `fateful asm` or `fateful assemble` command to assembler f8ful assembly into f8ful machine code.
 The input and output are both optional, and default to `stdin` and `stdout` respectively.
+Input is positional, being the first argument, and the output can be specified with the `-o` or `--output` flag.
 
-### Instructions
+### Instruction Set
 
-There are sixteen instructions in f8ful assembly.
+0. [ADD](#add)
+0. [SUB](#sub)
+0. [ADC](#adc)
+0. [SBB](#sbb)
+0. [NAND](#nand)
+0. [OR](#or)
+0. [CMP](#cmp)
+0. [MV](#mv)
+0. [LD](#ld)
+0. [ST](#st)
+0. [LDA](#lda)
+0. [LPM](#lpm)
+0. [PUSH](#push)
+0. [POP](#pop)
+0. [JNZ](#jnz)
+0. [HALT](#halt)
+
+#### ADD
+
+Machine Code: `0x00`
+
+Operation: Adds the first and second operand, storing the result in the first operand.
+
+```asm
+add <register>, <register/imm8>
+```
+
+#### SUB
+
+Machine Code: `0x01`
+
+Operation: Subtracts the second operand from the first, storing the result in the first operand.
+
+```asm
+sub <register>, <register/imm8>
+```
+
+#### ADC
+
+Machine Code: `0x02`
+
+Operation: Adds the first and second operands, plus an additional 1 if the carry bit is set, storing the result in the first operand.
+
+```asm
+adc <register>, <register/imm8>
+```
+
+#### SBB
+
+Machine Code: `0x03`
+
+Operation: Subtracts the second operand from the first, subtracting an additional 1 if the carry bit is set, storing the result in the first operand.
+
+```asm
+sbb <register>, <register/imm8>
+```
+
+#### NAND
+
+Machine Code: `0x04`
+
+Operation: Performs a bitwise NAND on the first and second operands, storing the result in the first operand.
+
+```asm
+nand <register>, <register/imm8>
+```
+
+#### OR
+
+Machine Code: `0x05`
+
+Operation: Performs a bitwise OR on the first and second operands,
+storing the result in the first operand.
+
+```asm
+or <register>, <register/imm8>
+```
 
 ## Emulator