Mercurial > lcfOS
comparison doc/utils.rst @ 381:6df89163e114
Fix section and ldr pseudo instruction
| author | Windel Bouwman |
|---|---|
| date | Sat, 26 Apr 2014 17:41:56 +0200 |
| parents | 8d07a4254f04 |
| children |
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| 380:67a584582aee | 381:6df89163e114 |
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| 27 Burg | 27 Burg |
| 28 ---- | 28 ---- |
| 29 | 29 |
| 30 .. automodule:: pyburg | 30 .. automodule:: pyburg |
| 31 | 31 |
| 32 | |
| 33 Machine descriptions | |
| 34 -------------------- | |
| 35 | |
| 36 There are some attempts made already to describe machines in a Domain | |
| 37 Specific Language (DSL). Examples of these are: | |
| 38 - Tablegen (llvm) | |
| 39 - cgen (gnu) | |
| 40 - LISA (Aachen) | |
| 41 - nML (Berlin) | |
| 42 - SLED (Specifying representations of machine instructions (norman ramsey and Mary F. Fernandez)) | |
| 43 | |
| 44 | |
| 45 The goal of a machine description file is to describe a file and generate | |
| 46 tools like assemblers, disassemblers, linkers, debuggers and simulators. | |
| 47 | |
| 48 Advantage of using this approach is that porting these tools is a semi automated | |
| 49 process. Rewriting all of these tools from scratch is tedious and errorprone. | |
| 50 | |
| 51 Concepts to use in this language: | |
| 52 - Single stream of instructions | |
| 53 - State stored in memory | |
| 54 - Pipelining | |
| 55 - Instruction semantics | |
| 56 | |
| 57 Each instruction has the following properties: | |
| 58 - Bit representation | |
| 59 - Assembly language representation | |
| 60 - Semantic action | |
| 61 | |
| 62 Optionally a description in terms of compiler code generation can be attached | |
| 63 to this. But perhaps this clutters the description too much and we need to put | |
| 64 it elsewhere. | |
| 65 | |
| 66 | |
| 67 The description language can help to expand these descriptions by expanding | |
| 68 the permutations. | |
| 69 | |
| 70 | |
| 71 |