sb!kernel::undefined-alien-variable-error
sb!kernel::undefined-alien-function-error
sb!kernel::memory-fault-error
+ sb!kernel::unhandled-trap-error
sb!di::handle-breakpoint
sb!di::handle-single-step-trap
fdefinition-object
*control-stack-end*
;; interrupt handling
+ *alloc-signal*
*free-interrupt-context-index*
sb!unix::*interrupts-enabled*
sb!unix::*interrupt-pending*