src/assembly/x86-64/tramps.lisp

   1 ;;;; Undefined-function and closure trampoline definitions
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5
   6 (in-package "SB!VM")
   7
   8 (define-assembly-routine
   9     (undefined-tramp (:return-style :none))
  10     ((:temp rax descriptor-reg rax-offset))
  11   (inst pop (make-ea :qword :base rbp-tn :disp n-word-bytes))
  12   (emit-error-break nil cerror-trap (error-number-or-lose 'undefined-fun-error) (list rax))
  13   (inst push (make-ea :qword :base rbp-tn :disp n-word-bytes))
  14   (inst jmp
  15         (make-ea :qword :base rax
  16                         :disp (- (* fdefn-raw-addr-slot
  17                                     n-word-bytes)
  18                                  other-pointer-lowtag))))
  19
  20 (define-assembly-routine
  21     (undefined-alien-tramp (:return-style :none))
  22     ()
  23   (inst pop (make-ea :qword :base rbp-tn :disp n-word-bytes))
  24   (error-call nil 'undefined-alien-fun-error rbx-tn))
  25
  26 ;;; the closure trampoline - entered when a global function is a closure
  27 ;;; and the function is called "by name" (normally, as when it is the
  28 ;;; head of a form) via an FDEFN. Register %RAX holds the fdefn address,
  29 ;;; but the simple-fun which underlies the closure expects %RAX to be the
  30 ;;; closure itself. So we grab the closure out of the fdefn pointed to,
  31 ;;; then jump to the simple-fun that the closure points to.
  32 (define-assembly-routine
  33     (closure-tramp (:return-style :none))
  34     ()
  35   (loadw rax-tn rax-tn fdefn-fun-slot other-pointer-lowtag)
  36   (inst jmp (make-ea-for-object-slot rax-tn closure-fun-slot fun-pointer-lowtag)))
  37
  38 (define-assembly-routine
  39     (funcallable-instance-tramp (:return-style :none))
  40     ()
  41   (loadw rax-tn rax-tn funcallable-instance-function-slot fun-pointer-lowtag)
  42   (inst jmp (make-ea-for-object-slot rax-tn closure-fun-slot fun-pointer-lowtag)))