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Diffstat (limited to 'twasm/README.md')
| -rw-r--r-- | twasm/README.md | 109 |
1 files changed, 63 insertions, 46 deletions
diff --git a/twasm/README.md b/twasm/README.md index 77905a6..774f568 100644 --- a/twasm/README.md +++ b/twasm/README.md @@ -22,11 +22,14 @@ tokeniser ------------------------ byte(s) -> next byte(s) ------------------------ -Newline -> Newline +Newline -> Label + -> Newline -> Komment -> Operator -> Directive +Label -> Newline + Komment -> Newline Operator -> Newline @@ -45,37 +48,6 @@ Directive -> Newline ------------------------ ``` -not yet implemented: - -``` ------------------------- -operand parser ------------------------- -byte(s) -> next byte(s) ------------------------- -START -> '[' - -> Register - -> Constant - -'[' -> Register - -> Constant - -']' -> END - -Register -> IF #[, ']' - -> Operator - -Constant -> IF #[, ']' - -> Operator - -Operator -> IF NOT #R, Register - -> Constant ------------------------- -:R: = whether a register has been found -:[: = whether a '[' has been found ------------------------- -``` - ### memory map ``` @@ -88,6 +60,10 @@ Operator -> IF NOT #R, Register +------ 0x00060000 ------+ | test arena | +------ 0x00050000 ------+ +| label table | ++------ 0x00040000 ------+ +| awaiting label table | ++------ 0x00030000 ------+ | stack (rsp) | +------------------------+ | input | @@ -105,6 +81,7 @@ each word represents a token on the token table. each token gets loaded into the token table with the following form: ``` +2 bytes +----------+ | 15 0 | +----------+ @@ -112,6 +89,40 @@ each token gets loaded into the token table with the following form: +----------+ ``` +#### label table (LT) + +label definitions are stored and recalled from this table. The memory addresses are relative to the start of the program + +``` +16 bytes ++---------+ +| 127 64 | ++---------+ +| address | ++---------+ +| 63 0 | ++---------+ +| hash | ++---------+ +``` + +#### awaiting label table (ALT) + +forward references are stored in this table to be filled in after assembly is otherwise complete. The memory addresses are relative to the start of the program + +``` +16 bytes ++----------+----------+------------------+---------+ +| 127 105 | 104 104 | 103 96 | 95 64 | ++----------+----------+------------------+---------+ +| reserved | abs flag | # bytes reserved | address | ++----------+----------+------------------+---------+ +| 63 0 | ++--------------------------------------------------+ +| hash | ++--------------------------------------------------+ +``` + ### internal data structures #### `tokens.[operators|registers]` @@ -121,6 +132,7 @@ contains tokens by their type. Intended to be searched by token name to get the each entry is in the following form: ``` +6 bytes +----------+--------------------------------+ | 47 32 | 31 0 | +----------+--------------------------------+ @@ -129,26 +141,16 @@ each entry is in the following form: ``` -example implementation: - -```nasm -tokens - .registers: - dd "r8" - dw 0x0008 - .by_name3: ; this is required for futureproofness; the caller can use this to - ; find the size of registers.by_name2 -``` - note that tokens longer than 4 bytes are problematic :/ #### `tokens.by_id` -contains some tokens with their metadata. Some tokens have embedded information (`0x10XX` for instance). Those will not have entries in this table, being handled instead inside the assemble function itself. +contains some tokens with their metadata. Some tokens have embedded information (`0x10XX` for instance). Those do not have entries in this table, being handled instead inside the assemble function itself. metadata about some tokens in the following form: ``` +4 bytes +----------------+----------+-------+----------+ | 31 24 | 23 20 | 19 16 | 15 0 | +----------------+----------+-------+----------+ @@ -168,6 +170,7 @@ the `type` hex digit is defined as the following: type metadata for the different types is as follows: ``` +1 byte +----------+ | type 0x0 | +----------+ @@ -178,6 +181,7 @@ type metadata for the different types is as follows: ``` ``` +1 byte +-------------------------------+ | type 0x1 | +----------+--------------------+ @@ -188,6 +192,7 @@ type metadata for the different types is as follows: ``` ``` +1 byte +------------------------------+ | type 0x2 | +----------+-----------+-------+ @@ -210,6 +215,7 @@ type metadata for the different types is as follows: entries are as follows: ``` +16 bytes +------------------------------+ | 0 operand operators | +------------------------------+ @@ -230,6 +236,7 @@ entries are as follows: | reserved | opcode | token ID | +----------+--------+----------+ +16 bytes +-------------------------------------------------------------+ | 1 operand operators | +-------------------------------------------------------------+ @@ -252,6 +259,7 @@ entries are as follows: | | dst=r/m | | +----------+---------------+----------------------------------+ +16 bytes +----------------------------------------------+ | 2 operand operators | +----------------------------------------------+ @@ -389,14 +397,23 @@ supported tokens are listed below | ret | 0x005A | | | cmp | 0x005B | | | | 0x10XX | some memory address; `XX` is as specified below | -| | 0xFEXX | used to pass some raw value `XX` in place of a token id | +| | 0x20XX | some constant; `XX` is as specified below | +| | 0x3XXX | some label definition; `XXX` is its entry index in the label table | +| | 0x4XXX | some label reference; `XXX` is its entry index in the label table +| | 0xFEXX | used to pass some raw value `XX` in place of a token id to a couple of functions that mention this as a feature. If the function doesn't mention it, it will lead to undefined behaviour | | | 0xFFFF | unrecognised token | values of `XX` in `0x10XX`: | XX | description | |------|-------------| -| 0x00 | following byte is the token ID of some register | +| 0x00 | following word is the token ID of some register | + +values of `XX` in `0x20XX`: + +| XX | description | +|------|-------------| +| 0x00 | following 8 bytes are the constant's value | ### example program |