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| author | Kartik Agaram <vc@akkartik.com> | 2018-11-26 00:56:43 -0800 |
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| committer | Kartik Agaram <vc@akkartik.com> | 2018-11-26 00:56:43 -0800 |
| commit | 7e00968c99f97e13be8f5269feaf7fd1d33ecd33 (patch) | |
| tree | eb5a77578e07e170f4e5cff987b33b08501fa7ae /subx | |
| parent | e5cbbea435524ecd77f4ebabaab873720c64464f (diff) | |
| download | mu-7e00968c99f97e13be8f5269feaf7fd1d33ecd33.tar.gz | |
4781
Diffstat (limited to 'subx')
| -rw-r--r-- | subx/Readme.md | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/subx/Readme.md b/subx/Readme.md index f131c5d0..cfc7a3fb 100644 --- a/subx/Readme.md +++ b/subx/Readme.md @@ -112,6 +112,8 @@ $ echo $? 55 ``` +[](https://travis-ci.org/akkartik/mu) + The rest of this Readme elaborates on the syntax for SubX programs, starting with a few prerequisites about the x86 instruction set. @@ -225,7 +227,7 @@ fairly directly, with only minimal-going-on-zero reliance on a C compiler. ## The syntax of SubX programs SubX programs map to the same ELF binaries that a conventional Linux system -uses. Linux ELF binaries consist of a series of segments. In particular, they +uses. Linux ELF binaries consist of a series of _segments_. In particular, they distinguish between code and data. Correspondingly, SubX programs consist of a series of segments, each starting with a header line: `==` followed by a name. The first segment is assumed to be for code, and the second for data. By @@ -246,11 +248,11 @@ You can reuse segment names: ...C... ``` -The code segment now contains fragment `A` as well as `C`. `C` comes _before_ -`A`. This behavior allows me to split SubX programs between multiple _layers_. -A program built with just layer 1 would start executing at layer 1's first -instruction, while one built with layer 1 and layer 2 (in that order) would -start executing at layer 2's first instruction. +The code segment now contains the instructions of `A` as well as `C`. `C` +comes _before_ `A`. This order allows me to split SubX programs between +multiple _layers_. A program built with just layer 1 would start executing at +layer 1's first instruction, while one built with layer 1 and layer 2 (in that +order) would start executing at layer 2's first instruction. Within the code segment, each line contains a comment, label or instruction. Comments start with a `#` and are ignored. Labels should always be the first @@ -320,12 +322,12 @@ Running `subx` will transparently compile it as necessary. `subx` currently has the following sub-commands: -* `subx test`: provides some online help. +* `subx help`: some helpful documentation to have at your fingertips. * `subx test`: runs all automated tests. -* `subx translate <input files> -o <output ELF binary>`: translates text files - containing hex bytes and macros into an executable ELF binary. +* `subx translate <input files> -o <output ELF binary>`: translates `.subx` + files into an executable ELF binary. * `subx run <ELF binary>`: simulates running the ELF binaries emitted by `subx translate`. Useful for debugging, and also enables more thorough testing of |