In the RISC-V psABI, the vector registers v0-v31 are all caller-saved.
The vstart, vl, and vtype CSRs are also caller-saved.
The vxrm and vxsat fields have thread storage duration.
Executing a system call causes v0-v31 to become unspecified.
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Note
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This scheme allows system calls that cause context switches to avoid saving and later restoring the vector registers. |
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Note
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The values that v0-v31 assume after a system call cannot expose
information from other processes, so typically the registers will either
remain intact or will be zeroed.
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