forked from AbleOS/ableos
30 lines
1 KiB
Markdown
30 lines
1 KiB
Markdown
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# C ABI (proposal)
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## C datatypes
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| C Type | Description | Size (B) |
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|:------------|:-------------------------|-------------:|
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| char | Character / byte | 8 |
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| short | Short integer | 16 |
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| int | Integer | 32 |
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| long | Long integer | 64 |
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| long long | Long long integer | 64 |
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| T* | Pointer | 64 |
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| float | Single-precision float | 32 |
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| double | Double-precision float | 64 |
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| long double | Extended-precision float | **Bikeshed** |
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## Registers
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| Register | ABI Name | Description | Saver |
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|:---------|:---------|:---------------|:-------|
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| `r0` | — | Zero register | N/A |
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| `r1` | `ra` | Return address | Caller |
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| `r2` | `sp` | Stack pointer | Callee |
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| `r3` | `tp` | Thread pointer | N/A |
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**TODO:** Parameters
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**TODO:** Saved
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**TODO:** Temp
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