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;;; -*- Package: C; Log: C.Log -*-
;;;
;;; **********************************************************************
;;; This code was written as part of the Spice Lisp project at
;;; Carnegie-Mellon University, and has been placed in the public domain.
;;; If you want to use this code or any part of Spice Lisp, please contact
;;; Scott Fahlman (FAHLMAN@CMUC).
;;; **********************************************************************
;;;
;;; This file contains the VM definition of function call for the RT.
;;;
;;; Written by Rob MacLachlan
;;;
(in-package 'c)
;;;; Interfaces to IR2 conversion:
;;; Standard-Argument-Location -- Interface
;;;
;;; Return a wired TN describing the N'th full call argument passing
;;; location.
;;;
(defun standard-argument-location (n)
(declare (type unsigned-byte n))
(if (< n register-arg-count)
(make-wired-tn *any-primitive-type*
register-arg-scn (elt register-arg-offsets n))
(make-wired-tn *any-primitive-type* stack-arg-scn n)))
;;; Make-Return-PC-Passing-Location -- Interface
;;;
;;; Make a passing location TN for a local call return PC. If standard is
;;; true, then use the standard (full call) location, otherwise use any legal
;;; location. Even in the non-standard case, this may be restricted by a
;;; desire to use a subroutine call instruction.
;;;
(defun make-return-pc-passing-location (standard)
(if standard
(make-wired-tn *any-primitive-type* register-arg-scn return-pc-offset)
(make-restricted-tn *any-primitive-type* register-arg-scn)))
;;; Make-Old-Fp-Passing-Location -- Interface
;;;
;;; Similar to Make-Return-PC-Passing-Location, but makes a location to pass
;;; Old-Fp in. This is (obviously) wired in the standard convention, but is
;;; totally unrestricted in non-standard conventions, since we can always fetch
;;; it off of the stack using the arg pointer.
;;;
(defun make-old-fp-passing-location (standard)
(if standard
(make-wired-tn *any-primitive-type* register-arg-scn old-fp-offset)
(make-normal-tn *any-primitive-type*)))
;;; Make-Old-Fp-Save-Location, Make-Return-PC-Save-Location -- Interface
;;;
;;; Make the TNs used to hold Old-Fp and Return-PC within the current
;;; function. We treat these specially so that the debugger can find them at a
;;; known location.
;;;
(defun make-old-fp-save-location (env)
(environment-live-tn
(make-wired-tn *any-primitive-type* stack-arg-scn old-fp-save-offset)
env))
;;;
(defun make-return-pc-save-location (env)
(environment-live-tn
(make-wired-tn *any-primitive-type* stack-arg-scn return-pc-save-offset)
env))
;;; Make-Argument-Count-Location -- Interface
;;;
;;; Make a TN for the standard argument count passing location. We only
;;; need to make the standard location, since a count is never passed when we
;;; are using non-standard conventions.
;;;
(defun make-argument-count-location ()
(make-wired-tn *any-primitive-type* register-arg-scn argument-count-offset))
;;; MAKE-NFP-TN -- Interface
;;;
;;; Make a TN to hold the number-stack frame pointer. This is allocated
;;; once per component, and is component-live.
;;;
(defun make-nfp-tn ()
(component-live-tn
(make-restricted-tn *any-primitive-type* register-arg-scn)))
;;; MAKE-STACK-POINTER-TN ()
;;;
(defun make-stack-pointer-tn ()
(make-normal-tn *any-primitive-type*))
;;; MAKE-NUMBER-STACK-POINTER-TN ()
;;;
(defun make-number-stack-pointer-tn ()
(make-normal-tn *any-primitive-type*))
;;; Make-Unknown-Values-Locations -- Interface
;;;
;;; Return a list of TNs that can be used to represent an unknown-values
;;; continuation within a function.
;;;
(defun make-unknown-values-locations ()
(list (make-stack-pointer-tn)
(make-normal-tn *any-primitive-type*)))
;;; Select-Component-Format -- Interface
;;;
;;; This function is called by the Entry-Analyze phase, allowing
;;; VM-dependent initialization of the IR2-Component structure. We push
;;; placeholder entries in the Constants to leave room for the component name,
;;; code vector and debug info.
;;;
(defun select-component-format (component)
(declare (type component component))
(dotimes (i 3)
(vector-push-extend nil
(ir2-component-constants (component-info component))))
(undefined-value))
;;;; Frame hackery:
;;; Used for setting up the Old-Fp in local call.
;;;
(define-vop (current-fp)
(:results (val :scs (any-reg descriptor-reg)))
(:generator 1
(inst lr val fp-tn)))
#| Since we don't have a number stack yet, shouldn't be emitted.
;;; Used for computing the caller's NFP for use in known-values return. Only
;;; works assuming there is no variable size stuff on the nstack.
;;;
(define-vop (compute-old-nfp)
(:results (val :scs (any-reg descriptor-reg)))
(:vop-var vop)
(:generator 1
(let ((nfp (current-nfp-tn vop)))
(when nfp
(inst cal val nfp (- (* 4 (sb-allocated-size 'number-stack))))))))
|#
;;; In an XEP, allocate frames for this function on the control stack (and
;;; number stack if any). We get to emit the start label, since we might need
;;; to emit variable cruft to align it, etc.
;;;
(define-vop (xep-allocate-frame)
(:info start-lab)
(:generator 1
(emit-label start-lab)
(inst cal sp-tn fp-tn (* 4 (sb-allocated-size 'stack)))))
;;; Allocate the frame for the function we are about to call, returning the
;;; frame pointer(s).
;;;
(define-vop (allocate-frame)
(:results (res :scs (any-reg descriptor-reg)) (nfp))
(:info callee)
(:ignore nfp callee)
(:generator 2
(inst lr res sp-tn)
(inst cal sp-tn sp-tn (* 4 (sb-allocated-size 'stack)))))
;;; Allocate a partial frame for passing stack arguments in a full call. Nargs
;;; is the number of arguments passed. If no stack arguments are passed, then
;;; we don't have to do anything.
;;;
(define-vop (allocate-full-call-frame)
(:info nargs)
(:results (res :scs (any-reg descriptor-reg)
:load-if (> nargs register-arg-count)))
(:generator 2
(when (> nargs register-arg-count)
(inst lr res sp-tn)
(inst cal sp-tn sp-tn (* 4 nargs)))))
;;; Default-Unknown-Values -- Internal
;;;
;;; Emit code needed at the return-point from an unknown-values call for a
;;; fixed number of values. Values is the head of the TN-Ref list for the
;;; locations that the values are to be received into. Nvals is the number of
;;; values that are to be received (should equal the length of Values). Node
;;; is the node to use for source context in emitted code.
;;;
;;; Move-Temp and Nil-Temp are Descriptor-Reg TNs used as temporaries.
;;;
;;; This code exploits the fact that in the unknown-values convention, a
;;; single value return returns at the return PC + 4, whereas a return of other
;;; than one value returns directly at the return PC.
;;;
;;; If 0 or 1 values are expected, then we just emit an instruction to reset
;;; the SP (which will only be executed when other than 1 value is returned.)
;;;
;;; In the general case, we have to do three things:
;;; -- Default unsupplied register values. This need only be done when a
;;; single value is returned, since register values are defaulted by the
;;; called in the non-single case.
;;; -- Default unsupplied stack values. This needs to be done whenever there
;;; are stack values.
;;; -- Reset SP. This must be done whenever other than 1 value is returned,
;;; regardless of the number of values desired.
;;;
;;; The general-case code looks like this:
#|
br regs-defaulted ; Skip if MVs
cau a1 0 nil-16 ; Default register values
...
loadi nargs 1 ; Force defaulting of stack values
lr args sp ; Set up args for SP resetting
regs-defaulted
cau nil-temp 0 nil-16 ; Cache nil
cmpi nargs 3 ; If 4'th value unsupplied...
blex default-value-4 ; jump to default code
loadw move-temp old-fp-tn 3 ; Move value to correct location.
store-stack-tn val4-tn move-temp
cmpi nargs 4 ; Check 5'th value, etc.
blex default-value-5
loadw move-temp old-fp-tn 4
store-stack-tn val5-tn move-temp
...
defaulting-done
lr sp args ; Reset SP.
<end of code>
<elsewhere>
default-value-4
store-stack-tn val4-tn nil-temp ; Nil out 4'th value.
default-value-5
store-stack-tn val5-tn nil-temp ; Nil out 5'th value.
...
br defaulting-done
|#
;;;
(defun default-unknown-values (node values nvals move-temp nil-temp)
(declare (type node node) (type (or tn-ref null) values)
(type unsigned-byte nvals) (type tn move-temp nil-temp))
(assemble node
(if (<= nvals 1)
(inst ai sp-tn old-fp-tn 0)
(let ((regs-defaulted (gen-label))
(defaulting-done (gen-label)))
(inst bnb :pz regs-defaulted)
(do ((i 1 (1+ i))
(val (tn-ref-across values) (tn-ref-across val)))
((= i (min nvals register-arg-count)))
(inst cau (tn-ref-tn val) zero-tn clc::nil-16))
(when (> nvals register-arg-count)
(loadi nargs-tn 1)
(inst lr old-fp-tn sp-tn))
(emit-label regs-defaulted)
(when (> nvals register-arg-count)
(inst cau nil-temp zero-tn clc::nil-16)
(collect ((defaults))
(do ((i register-arg-count (1+ i))
(val (do ((i 0 (1+ i))
(val values (tn-ref-across val)))
((= i register-arg-count) val))
(tn-ref-across val)))
((null val))
(let ((default-lab (gen-label))
(tn (tn-ref-tn val)))
(defaults (cons default-lab tn))
(cmpi nargs-tn i)
(inst bnbx :gt default-lab)
(loadw move-temp old-fp-tn i)
(store-stack-tn tn move-temp)))
(emit-label defaulting-done)
(inst lr sp-tn old-fp-tn)
(unassemble
(assemble-elsewhere node
(dolist (def (defaults))
(emit-label (car def))
(store-stack-tn (cdr def) nil-temp))
(inst bnb :pz defaulting-done))))))))
(undefined-value))
;;;; Unknown values receiving:
;;; Receive-Unknown-Values -- Internal
;;;
;;; Emit code needed at the return point for an unknown-values call for an
;;; arbitrary number of values.
;;;
;;; We do the single and non-single cases with no shared code: there doesn't
;;; seem to be any potential overlap, and receiving a single value is more
;;; important efficiency-wise.
;;;
;;; When there is a single value, we just push it on the stack, returning
;;; the old SP and 1.
;;;
;;; When there is a variable number of values, we move all of the argument
;;; registers onto the stack, and return Old-Fp and Nargs.
;;;
;;; Old-Fp and Nargs are TNs wired to the named locations. We must
;;; explicitly allocate these TNs, since their lifetimes overlap with the
;;; results Start and Count (also, it's nice to be able to target them).
;;;
(defun receive-unknown-values (node old-fp nargs start count)
(declare (type node node) (type tn old-fp nargs start count))
(assemble node
(let ((variable-values (gen-label))
(done (gen-label)))
(inst bnb :pz variable-values)
(inst inc sp-tn 4)
(storew (first register-argument-tns) sp-tn -1)
(inst cal start sp-tn -4)
(loadi count 1)
(emit-label done)
(unassemble
(assemble-elsewhere node
(emit-label variable-values)
(do ((arg register-argument-tns (rest arg))
(i 0 (1+ i)))
((null arg))
(storew (first arg) old-fp i))
(unless (location= start old-fp)
(inst lr start old-fp))
(unless (location= count nargs)
(inst lr count nargs))
(inst bnb :pz done)))))
(undefined-value))
;;; VOP that can be inherited by unknown values receivers. The main thing this
;;; handles is allocation of the result temporaries.
;;;
(define-vop (unknown-values-receiver)
(:results
(start :scs (descriptor-reg))
(count :scs (descriptor-reg)))
(:node-var node)
(:temporary (:sc descriptor-reg
:offset old-fp-offset
:from :eval :to (:result 0))
values-start)
(:temporary (:sc any-reg
:offset argument-count-offset
:from :eval :to (:result 1))
nvals))
;;;; Local call with unknown values convention return:
;;; Non-TR local call for a fixed number of values passed according to the
;;; unknown values convention.
;;;
;;; When initially emitted, Args reference the values to be passed.
;;; Representation selection changes the Args to reference the passing
;;; locations when it inserts the move-argument VOPs. Arg-Locs is the list of
;;; passing locations used by representation selection.
;;;
;;; Values are the return value locations (wired to the standard passing
;;; locations).
;;;
;;; Save is the save info, which we can ignore since saving has been done.
;;; Return-PC is the TN that the return PC should be passed in.
;;; Target is a continuation pointing to the start of the called function.
;;; Nvals is the number of values received.
;;;
;;; Note: we can't use normal load-tn allocation for the fixed args, since all
;;; registers may be tied up by the more operand. Instead, we use
;;; MAYBE-LOAD-STACK-TN.
;;;
(define-vop (call-local)
(:args (fp)
(nfp)
(args :more t))
(:results (values :more t))
(:save-p t)
(:move-args :local-call)
(:info arg-locs callee target nvals)
(:ignore arg-locs args nfp)
(:node-var node)
(:vop-var vop)
(:temporary (:scs (descriptor-reg)) move-temp nil-temp)
(:temporary (:sc stack
:offset env-save-offset)
env-save)
(:generator 5
(store-stack-tn env-save env-tn)
(maybe-load-stack-tn fp-tn fp)
(inst bali (callee-return-pc-tn callee) target)
(note-this-location vop :unknown-return)
(unassemble
(default-unknown-values node values nvals move-temp nil-temp))
(load-stack-tn env-tn env-save)))
;;; Non-TR local call for a variable number of return values passed according
;;; to the unknown values convention. The results are the start of the values
;;; glob and the number of values received.
;;;
(define-vop (multiple-call-local unknown-values-receiver)
(:args (fp)
(nfp)
(args :more t))
(:save-p t)
(:move-args :local-call)
(:info arg-locs callee target)
(:ignore arg-locs args nfp)
(:vop-var vop)
(:temporary (:sc stack
:offset env-save-offset)
env-save)
(:generator 20
(store-stack-tn env-save env-tn)
(maybe-load-stack-tn fp-tn fp)
(inst bali (callee-return-pc-tn callee) target)
(note-this-location vop :unknown-return)
(unassemble
(receive-unknown-values node values-start nvals start count))
(load-stack-tn env-tn env-save)))
;;;; Local call with known values return:
;;; Non-TR local call with known return locations. Known-value return works
;;; just like argument passing in local call.
;;;
(define-vop (known-call-local)
(:args (fp)
(nfp)
(args :more t))
(:results
(res :more t))
(:move-args :local-call)
(:save-p t)
(:info arg-locs callee target)
(:ignore arg-locs args res nfp)
(:vop-var vop)
(:generator 5
(maybe-load-stack-tn fp-tn fp)
(inst bali (callee-return-pc-tn callee) target)
(note-this-location vop :known-return)))
;;; Return from known values call. We receive the return locations as
;;; arguments to terminate their lifetimes in the returning function. We
;;; restore FP and SP and jump to the Return-PC.
;;;
;;; Note: we can't use normal load-tn allocation for the fixed args, since all
;;; registers could get tied up by the more operand. Instead, we use
;;; MAYBE-LOAD-STACK-TN into preallocated temporaries.
;;;
(define-vop (known-return)
(:args
(old-fp)
(return-pc)
(vals :more t))
(:temporary (:sc descriptor-reg :from (:argument 0)) old-fp-temp)
(:temporary (:sc descriptor-reg :from (:argument 1)) return-pc-temp)
(:move-args :known-return)
(:info val-locs)
(:ignore val-locs vals)
(:generator 6
(maybe-load-stack-tn old-fp-temp old-fp)
(maybe-load-stack-tn return-pc-temp return-pc)
(inst lr sp-tn fp-tn)
(inst bnbrx :pz return-pc-temp)
(inst lr fp-tn old-fp-temp)))
;;;; Full call:
;;;
;;; There is something of a cross-product effect with full calls. Different
;;; versions are used depending on whether we know the number of arguments or
;;; the name of the called function, and whether we want fixed values, unknown
;;; values, or a tail call.
;;;
;;; In full call, the arguments are passed creating a partial frame on the
;;; stack top and storing stack arguments into that frame. On entry to the
;;; callee, this partial frame is pointed to by FP. If there are no stack
;;; arguments, we don't bother allocating a partial frame, and instead set FP
;;; to SP just before the call.
;;; Define-Full-Call -- Internal
;;;
;;; This macro helps in the definition of full call VOPs by avoiding code
;;; replication in defining the cross-product VOPs.
;;;
;;; Name is the name of the VOP to define.
;;;
;;; Named is true if the first argument is a symbol whose global function
;;; definition is to be called.
;;;
;;; Return is either :Fixed, :Unknown or :Tail:
;;; -- If :Fixed, then the call is for a fixed number of values, returned in
;;; the standard passing locations (passed as result operands).
;;; -- If :Unknown, then the result values are pushed on the stack, and the
;;; result values are specified by the Start and Count as in the
;;; unknown-values continuation representation.
;;; -- If :Tail, then do a tail-recursive call. No values are returned.
;;; The Old-Fp and Return-PC are passed as the second and third arguments.
;;;
;;; In non-tail calls, the pointer to the stack arguments is passed as the last
;;; fixed argument. If Variable is false, then the passing locations are
;;; passed as a more arg. Variable is true if there are a variable number of
;;; arguments passed on the stack. Variable cannot be specified with :Tail
;;; return. TR variable argument call is implemented separately.
;;;
;;; In tail call with fixed arguments, the passing locations are passed as a
;;; more arg, but there is no new-FP, since the arguments have been set up in
;;; the current frame.
;;;
(defmacro define-full-call (name named return variable)
(assert (not (and variable (eq return :tail))))
`(define-vop (,name
,@(when (eq return :unknown)
'(unknown-values-receiver)))
(:args
,@(unless (eq return :tail)
`((new-fp :scs (descriptor-reg) :to :eval
,@(unless variable
`(:load-if (> nargs register-arg-count))))))
,(if named
'(name :scs (descriptor-reg)
:target name-pass)
'(function :scs (descriptor-reg) :to :eval))
,@(when (eq return :tail)
'((old-fp :scs (descriptor-reg)
:target old-fp-pass)
(return-pc :scs (descriptor-reg)
:target return-pc-pass)))
,@(unless variable '((args :more t))))
,@(when (eq return :fixed)
'((:results (values :more t))))
,@(unless (eq return :tail)
`((:save-p t)
(:node-var node)
(:vop-var vop)
(:temporary (:sc stack
:offset env-save-offset)
env-save)
,@(unless variable
'((:move-args :full-call)))))
(:info ,@(unless (or variable (eq return :tail)) '(arg-locs))
,@(unless variable '(nargs))
,@(when (eq return :fixed) '(nvals)))
(:ignore ,@(unless (or variable (eq return :tail)) '(arg-locs))
,@(unless variable '(args)))
(:temporary (:sc descriptor-reg
:offset old-fp-offset
:from (:argument 1)
:to :eval)
old-fp-pass)
(:temporary (:sc descriptor-reg
:offset return-pc-offset
:from (:argument ,(if (eq return :tail) 2 1))
:to :eval)
return-pc-pass)
,@(when named
`((:temporary (:sc descriptor-reg
:offset call-name-offset
:from (:argument ,(if (eq return :tail) 0 1))
:to :eval)
name-pass)
(:temporary (:scs (descriptor-reg)
:from (:argument ,(if (eq return :tail) 0 1))
:to :eval)
function)))
(:temporary (:sc descriptor-reg
:offset argument-count-offset
:to :eval)
nargs-pass)
,@(when variable
'((:temporary (:sc descriptor-reg
:offset (first register-arg-offsets)
:to :eval)
a0)
(:temporary (:sc descriptor-reg
:offset (second register-arg-offsets)
:to :eval)
a1)
(:temporary (:sc descriptor-reg
:offset (third register-arg-offsets)
:to :eval)
a2)))
,@(when (eq return :fixed)
'((:temporary (:scs (descriptor-reg)
:from :eval)
move-temp nil-temp)))
(:temporary (:scs (descriptor-reg)
:to :eval)
code offset)
(:generator ,(+ (if named 5 0)
(if variable 19 1)
(if (eq return :tail) 0 10)
15
(if (eq return :unknown) 25 0))
,@(when named
`((unless (location= name name-pass)
(inst lr name-pass name))
(loadw function name-pass (/ clc::symbol-definition 4))))
,@(if variable
`((inst lr nargs-pass sp-tn)
(inst s nargs-pass new-fp)
(inst sari nargs-pass 2)
(loadw a0 new-fp 0)
(loadw a1 new-fp 1)
(loadw a2 new-fp 2))
`((loadi nargs-pass nargs)))
(load-slot code function system:%function-code-slot)
(load-slot offset function system:%function-offset-slot)
(inst cas code code offset)
,@(if (eq return :tail)
'((unless (location= old-fp old-fp-pass)
(inst lr old-fp-pass old-fp))
(unless (location= return-pc return-pc-pass)
(inst lr return-pc-pass return-pc))
(inst bnbrx :pz code)
(inst lr env-tn function))
`((store-stack-tn env-save env-tn)
(inst lr old-fp-pass fp-tn)
,(if variable
'(inst lr fp-tn new-fp)
'(if (> nargs register-arg-count)
(inst lr fp-tn new-fp)
(inst lr fp-tn sp-tn)))
(inst balrx return-pc-pass code)
(inst lr env-tn function)
(no-op)))
,@(ecase return
(:fixed
'((note-this-location vop :unknown-return)
(unassemble
(default-unknown-values node values nvals move-temp nil-temp))))
(:unknown
'((note-this-location vop :unknown-return)
(unassemble
(receive-unknown-values node values-start nvals start count))))
(:tail))
,@(unless (eq return :tail)
'((load-stack-tn env-tn env-save))))))
(define-full-call call nil :fixed nil)
(define-full-call call-named t :fixed nil)
(define-full-call multiple-call nil :unknown nil)
(define-full-call multiple-call-named t :unknown nil)
(define-full-call tail-call nil :tail nil)
(define-full-call tail-call-named t :tail nil)
(define-full-call call-variable nil :fixed t)
(define-full-call multiple-call-variable nil :unknown t)
;;; Defined separately, since needs a MISCOP call that BLT's the arguments
;;; down.
;;;
;;; This miscop uses a non-standard calling convention so that the argument
;;; registers are free for loading of stack arguments. Old-Fp and the function
;;; are passed in the registers that they will ultimately go in: OLD-FP and
;;; ENV. Args is a pointer to the start of the arguments on the stack, and is
;;; passed in the special ARGS passing location. The Return-PC is passed in
;;; A3 rather than PC because the BALA trashes PC. We use BALA even though the
;;; miscop never returns, since there isn't any BA.
;;;
;;; [### We could easily code inline the special case of nargs <= 3.]
;;;
(define-vop (tail-call-variable)
(:args
(args :scs (descriptor-reg) :target args-pass)
(function :scs (descriptor-reg))
(old-fp :scs (descriptor-reg) :target old-fp-pass)
(return-pc :scs (descriptor-reg) :target a3))
(:temporary (:sc descriptor-reg
:offset old-fp-offset
:from (:argument 2))
old-fp-pass)
(:temporary (:sc descriptor-reg
:offset a3-offset
:from (:argument 3))
a3)
(:temporary (:sc descriptor-reg
:offset argument-pointer-offset
:from (:argument 0))
args-pass)
(:generator 75
(inst lr env-tn function)
(unless (location= args args-pass)
(inst lr args-pass args))
(unless (location= old-fp old-fp-pass)
(inst lr old-fp-pass old-fp))
(unless (location= return-pc a3)
(inst lr a3 return-pc))
(inst miscop 'clc::tail-call-variable)))
;;;; Unknown values return:
;;; Do unknown-values return of a fixed number of values. The Values are
;;; required to be set up in the standard passing locations. Nvals is the
;;; number of values returned.
;;;
;;; If returning a single value, then deallocate the current frame, restore
;;; FP and jump to the single-value entry at Return-PC + 4.
;;;
;;; If returning other than one value, then load the number of values returned,
;;; NIL out unsupplied values registers, restore FP and return at Return-PC.
;;; When there are stack values, we must initialize the argument pointer to
;;; point to the beginning of the values block (which is the beginning of the
;;; current frame.)
;;;
(define-vop (return)
(:args
(old-fp :scs (descriptor-reg any-reg))
(return-pc :scs (descriptor-reg) :target pc-save)
(values :more t))
(:ignore values)
(:info nvals)
(:temporary (:scs (descriptor-reg) :from (:argument 0)) pc-save)
(:temporary (:sc descriptor-reg
:offset (first register-arg-offsets)
:from (:eval 0)
:to (:eval 1))
a0)
(:temporary (:sc descriptor-reg
:offset (second register-arg-offsets)
:from (:eval 0)
:to (:eval 1))
a1)
(:temporary (:sc descriptor-reg
:offset (third register-arg-offsets)
:from (:eval 0)
:to (:eval 1))
a2)
(:temporary (:sc descriptor-reg
:offset argument-count-offset)
nvals-loc)
(:temporary (:sc descriptor-reg
:offset old-fp-offset)
vals-loc)
(:generator 6
(cond ((= nvals 1)
(inst lr sp-tn fp-tn)
(inst inc return-pc 4)
(inst bnbrx :pz return-pc)
(inst lr fp-tn old-fp))
(t
(loadi nvals-loc nvals)
(inst lr vals-loc fp-tn)
(inst cal sp-tn vals-loc (* nvals 4))
(inst lr fp-tn old-fp)
(unless (location= pc-save return-pc)
(inst lr pc-save return-pc))
(when (< nvals 3)
(inst cau a2 zero-tn clc::nil-16)
(when (< nvals 2)
(inst lr a1 a2))
(when (< nvals 1)
(inst lr a0 a2)))
(inst bnbr :pz pc-save)))))
;;; Do unknown-values return of an arbitrary number of values (passed on the
;;; stack.) We check for the common case of a single return value, and do that
;;; inline using the normal single value return convention. Otherwise, we
;;; branch off to code that calls a miscop.
;;;
;;; The Return-Multiple miscop uses a non-standard calling convention. For one
;;; thing, it doesn't return. We only use BALA because there isn't a BA
;;; instruction. Also, we don't use A0..A2 for argument passing, since the
;;; miscop will want to load these with values off of the stack. Instead, we
;;; pass Old-Fp and Count in the normal locations for these values. The
;;; pointer to the start of the return values is passed in the special ARGS
;;; location. Return-PC is passed in A3 since PC is trashed by the BALA.
;;;
(define-vop (return-multiple)
(:args
(old-fp :scs (descriptor-reg) :target old-fp-pass)
(return-pc :scs (descriptor-reg)
:target a3)
(start :scs (descriptor-reg)
:target vals-loc)
(count :scs (descriptor-reg)
:target nvals-loc))
(:temporary (:sc descriptor-reg
:offset old-fp-offset
:from (:argument 0))
old-fp-pass)
(:temporary (:sc descriptor-reg
:offset a3-offset
:from (:argument 1))
a3)
(:temporary (:sc descriptor-reg
:offset argument-pointer-offset
:from (:argument 2))
vals-loc)
(:temporary (:sc descriptor-reg
:offset argument-count-offset
:from (:argument 3))
nvals-loc)
(:temporary (:sc descriptor-reg
:offset (first register-arg-offsets))
a0)
(:node-var node)
(:generator 13
(let ((non-single (gen-label)))
(cmpi count 1)
(inst bnbx :eq non-single)
(loadw a0 start)
(inst lr sp-tn fp-tn)
(inst inc return-pc 4)
(inst bnbrx :pz return-pc)
(inst lr fp-tn old-fp)
(unassemble
(assemble-elsewhere node
(emit-label non-single)
(unless (location= old-fp-pass old-fp)
(inst lr old-fp-pass old-fp))
(unless (location= a3 return-pc)
(inst lr a3 return-pc))
(unless (location= vals-loc start)
(inst lr vals-loc start))
(unless (location= nvals-loc count)
(inst lr nvals-loc count))
(inst miscop 'clc::return-multiple))))))
;;;; XEP hackery:
;;; Fetch the constant pool from the function entry structure.
;;;
(define-vop (setup-environment)
(:generator 5
(load-slot env-tn env-tn system:%function-entry-constants-slot)))
;;; Return the current Env as our result, then indirect throught the closure
;;; and the closure-entry to find the constant pool
;;;
(define-vop (setup-closure-environment)
(:results (closure :scs (descriptor-reg)))
(:generator 11
(inst lr closure env-tn)
(load-slot env-tn env-tn system:%function-name-slot)
(load-slot env-tn env-tn system:%function-entry-constants-slot)))
;;; Copy a more arg from the argument area to the end of the current frame.
;;; Fixed is the number of non-more arguments. This definition and the
;;; associated miscop assume that all the arguments and stuff are in their
;;; passing registers, and that all other non-dedicated registers are free.
;;;
;;; We sleazily save the return PC in NAME so that we can do a miscop call.
;;;
(define-vop (copy-more-arg)
(:temporary (:sc descriptor-reg :offset a3-offset) a3)
(:temporary (:sc descriptor-reg :offset call-name-offset) name)
(:info fixed)
(:generator 20
(loadi a3 fixed)
(inst lr name pc-tn)
(inst miscop 'clc::copy-more-arg)
(inst lr pc-tn name)))
;;; More args are stored consequtively on the stack, starting immediately at
;;; the context pointer.
;;;
(define-vop (more-arg word-index-ref)
(:variant 0)
(:translate %more-arg))
;;; Turn more arg (context, count) into a list.
;;;
(define-miscop listify-rest-args (context count)
:translate %listify-rest-args)
;;; Return the location and size of the more arg glob created by Copy-More-Arg.
;;; Supplied is the total number of arguments supplied (originally passed in
;;; NARGS.) Fixed is the number of non-rest arguments.
;;;
;;; We must duplicate some of the work done by Copy-More-Arg, since at that
;;; time the environment is in a pretty brain-damaged state, preventing this
;;; info from being returned as values. What we do is compute
;;; supplied - fixed, and return a pointer that many words below the current
;;; stack top.
;;;
(define-vop (more-arg-context)
(:args
(supplied :scs (any-reg descriptor-reg)))
(:info fixed)
(:results
(context :scs (descriptor-reg))
(count :scs (any-reg descriptor-reg)))
(:temporary (:scs (any-reg) :type fixnum) byte-size)
(:generator 5
(inst ai count supplied (- fixed))
(inst lr byte-size count)
(inst sli byte-size 2)
(inst lr context sp-tn)
(inst s context byte-size)))
;;; Signal wrong argument count error if Nargs isn't = to Count.
;;;
(define-vop (verify-argument-count)
(:args
(nargs :scs (any-reg descriptor-reg)))
(:info count)
(:vop-var vop)
(:save-p :compute-only)
(:generator 3
(let ((err-lab (generate-error-code vop clc::error-wrong-number-args
nargs)))
(cmpi nargs count)
(inst bnb :eq err-lab))))
;;; Signal an argument count error.
;;;
(define-vop (argument-count-error)
(:args (nargs :scs (any-reg descriptor-reg)))
(:vop-var vop)
(:save-p :compute-only)
(:generator 0
(error-call clc::error-wrong-number-args nargs)
(note-this-location vop :internal-error)))