diff options
Diffstat (limited to 'BinaryEncoding.md')
| -rw-r--r-- | BinaryEncoding.md | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/BinaryEncoding.md b/BinaryEncoding.md index c1c1a0c..799f529 100644 --- a/BinaryEncoding.md +++ b/BinaryEncoding.md @@ -53,6 +53,15 @@ represented by _at most_ ceil(_N_/7) bytes that may contain padding `0x80` or `0 Note: Currently, the only sizes used are `varint7`, `varint32` and `varint64`. +## Instruction Opcodes + +In the MVP, the opcodes of [instructions](Semantics.md) are all encoded in a +single byte since there are fewer than 256 opcodes. Future features like +[SIMD](FutureFeatures.md#fixed-width-simd) and [atomics](FutureFeatures.md#threads) +will bring the total count above 256 and so an extension scheme will be +necessary, designating one or more single-byte values as prefixes for multi-byte +opcodes. + ## Language Types All types are distinguished by a negative `varint7` values that is the first byte of their encoding (representing a type constructor): @@ -456,7 +465,9 @@ count may be greater or less than the actual number of locals. # Function Bodies Function bodies consist of a sequence of local variable declarations followed by -[bytecode instructions](Semantics.md). Each function body must end with the `end` opcode. +[bytecode instructions](Semantics.md). Instructions are encoded as an +[opcode](#instruction-opcodes) followed by zero or more *immediates* as defined +by the tables below. Each function body must end with the `end` opcode. | Field | Type | Description | | ----- | ---- | ----------- | |