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Diffstat (limited to 'doc/ExtendingGuide.md')
| -rw-r--r-- | doc/ExtendingGuide.md | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/doc/ExtendingGuide.md b/doc/ExtendingGuide.md index 4533b8b..82a418d 100644 --- a/doc/ExtendingGuide.md +++ b/doc/ExtendingGuide.md @@ -33,6 +33,15 @@ existing definitions for privilege levels and exceptions in `riscv_types.sail`, and modifying the exception handling and privilege transition functions in `riscv_sys_control.sail`. +Modifying exception handling +---------------------------- + +An extension that needs to interact closely with exception handling +may need to capture additional information at the time of an +exception. This is supported using the `ext` field in the +`sync_exception` type in `riscv_sync_exception.sail`, which is where +the extension can store this information. + Adding low-level platform functionality --------------------------------------- @@ -91,6 +100,13 @@ The handling of the memory addresses involved during exception handling can be extending using the interface defined in `riscv_sys_exceptions.sail`. +Checking and transforming the program counter +--------------------------------------------- + +An extension might want to similarly check and transform accesses to +the program counter. This is supported by supplying implementations +of the functions defined in `riscv_pc_access.sail`. + Adding new instructions ----------------------- |