X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fassembly%2Fmips%2Farith.lisp;h=b409c34427364c1f14152d7316cc935f0bb0c800;hb=a7a9b1029e8b9e45a5b66d62e161cc476cb7b60c;hp=1b9d03967ac9cf051ae30bbe5487432e95446ecd;hpb=4ae1b794a5d6a90794468cf8017f5307f2c30dfe;p=sbcl.git

diff --git a/src/assembly/mips/arith.lisp b/src/assembly/mips/arith.lisp
index 1b9d039..b409c34 100644
--- a/src/assembly/mips/arith.lisp
+++ b/src/assembly/mips/arith.lisp
@@ -1,126 +1,174 @@
+;;;; stuff to handle simple cases for generic arithmetic
+
+;;;; This software is part of the SBCL system. See the README file for
+;;;; more information.
+;;;;
+;;;; This software is derived from the CMU CL system, which was
+;;;; written at Carnegie Mellon University and released into the
+;;;; public domain. The software is in the public domain and is
+;;;; provided with absolutely no warranty. See the COPYING and CREDITS
+;;;; files for more information.
+
 (in-package "SB!VM")
 
 
+
+;;;; Addition and subtraction.
+
+;;; static-fun-offset returns the address of the raw_addr slot of
+;;; a static function's fdefn.
+
+;;; Note that there is only one use of static-fun-offset outside this
+;;; file (in genesis.lisp)
+
 (define-assembly-routine (generic-+
-			  (:cost 10)
-			  (:return-style :full-call)
-			  (:translate +)
-			  (:policy :safe)
-			  (:save-p t))
-			 ((:arg x (descriptor-reg any-reg) a0-offset)
-			  (:arg y (descriptor-reg any-reg) a1-offset)
-
-			  (:res res (descriptor-reg any-reg) a0-offset)
-
-			  (:temp temp non-descriptor-reg nl0-offset)
-			  (:temp lip interior-reg lip-offset)
-			  (:temp lra descriptor-reg lra-offset)
-			  (:temp nargs any-reg nargs-offset)
-			  (:temp ocfp any-reg ocfp-offset))
-  (inst b DO-STATIC-FUN)
-  (inst nop)
-  #+nil
-  (progn
-    (inst and temp x 3)
-    (inst bne temp DO-STATIC-FUN)
-    (inst and temp y 3)
-    (inst bne temp DO-STATIC-FUN)
-    (inst nop)
-    (inst add res x y)
-    (lisp-return lra lip :offset 2))
+                          (:cost 10)
+                          (:return-style :full-call)
+                          (:translate +)
+                          (:policy :safe)
+                          (:save-p t))
+                         ((:arg x (descriptor-reg any-reg) a0-offset)
+                          (:arg y (descriptor-reg any-reg) a1-offset)
+
+                          (:res res (descriptor-reg any-reg) a0-offset)
+
+                          (:temp temp non-descriptor-reg nl0-offset)
+                          (:temp temp1 non-descriptor-reg nl1-offset)
+                          (:temp temp2 non-descriptor-reg nl2-offset)
+                          (:temp pa-flag non-descriptor-reg nl4-offset)
+                          (:temp lra descriptor-reg lra-offset)
+                          (:temp lip interior-reg lip-offset)
+                          (:temp nargs any-reg nargs-offset)
+                          (:temp ocfp any-reg ocfp-offset))
+  (inst or temp x y)
+  (inst and temp fixnum-tag-mask)
+  (inst bne temp DO-STATIC-FUN)
+  (inst addu temp x y)
+  ;; check for overflow
+  (inst xor temp1 temp x)
+  (inst xor temp2 temp y)
+  (inst and temp1 temp2)
+  (inst bltz temp1 DO-OVERFLOW)
+  (inst sra temp1 x n-fixnum-tag-bits)
+  (inst move res temp)
+  (lisp-return lra lip :offset 2)
+
+  DO-OVERFLOW
+  ;; We did overflow, so do the bignum version
+  (inst sra temp2 y n-fixnum-tag-bits)
+  (inst addu temp temp1 temp2)
+  (with-fixed-allocation (res pa-flag temp2 bignum-widetag
+                          (1+ bignum-digits-offset) nil)
+    (storew temp res bignum-digits-offset other-pointer-lowtag))
+  (lisp-return lra lip :offset 2)
 
   DO-STATIC-FUN
   (inst lw lip null-tn (static-fun-offset 'two-arg-+))
   (inst li nargs (fixnumize 2))
-  (inst move ocfp cfp-tn)
+  (move ocfp cfp-tn)
   (inst j lip)
-  (inst move cfp-tn csp-tn))
+  (move cfp-tn csp-tn t))
 
 
 (define-assembly-routine (generic--
-			  (:cost 10)
-			  (:return-style :full-call)
-			  (:translate -)
-			  (:policy :safe)
-			  (:save-p t))
-			 ((:arg x (descriptor-reg any-reg) a0-offset)
-			  (:arg y (descriptor-reg any-reg) a1-offset)
-
-			  (:res res (descriptor-reg any-reg) a0-offset)
-
-			  (:temp temp non-descriptor-reg nl0-offset)
-			  (:temp lip interior-reg lip-offset)
-			  (:temp lra descriptor-reg lra-offset)
-			  (:temp nargs any-reg nargs-offset)
-			  (:temp ocfp any-reg ocfp-offset))
-  (inst b DO-STATIC-FUN)
-  (inst nop)
-  #+nil
-  (progn
-    (inst and temp x 3)
-    (inst bne temp DO-STATIC-FUN)
-    (inst and temp y 3)
-    (inst bne temp DO-STATIC-FUN)
-    (inst nop)
-    (inst sub res x y)
-    (lisp-return lra lip :offset 2))
+                          (:cost 10)
+                          (:return-style :full-call)
+                          (:translate -)
+                          (:policy :safe)
+                          (:save-p t))
+                         ((:arg x (descriptor-reg any-reg) a0-offset)
+                          (:arg y (descriptor-reg any-reg) a1-offset)
+
+                          (:res res (descriptor-reg any-reg) a0-offset)
+
+                          (:temp temp non-descriptor-reg nl0-offset)
+                          (:temp temp1 non-descriptor-reg nl1-offset)
+                          (:temp temp2 non-descriptor-reg nl2-offset)
+                          (:temp pa-flag non-descriptor-reg nl4-offset)
+                          (:temp lra descriptor-reg lra-offset)
+                          (:temp lip interior-reg lip-offset)
+                          (:temp nargs any-reg nargs-offset)
+                          (:temp ocfp any-reg ocfp-offset))
+  (inst or temp x y)
+  (inst and temp fixnum-tag-mask)
+  (inst bne temp DO-STATIC-FUN)
+  (inst subu temp x y)
+  ;; check for overflow
+  (inst xor temp1 x y)
+  (inst xor temp2 x temp)
+  (inst and temp1 temp2)
+  (inst bltz temp1 DO-OVERFLOW)
+  (inst sra temp1 x n-fixnum-tag-bits)
+  (inst move res temp)
+  (lisp-return lra lip :offset 2)
+
+  DO-OVERFLOW
+  ;; We did overflow, so do the bignum version
+  (inst sra temp2 y n-fixnum-tag-bits)
+  (inst subu temp temp1 temp2)
+  (with-fixed-allocation (res pa-flag temp2 bignum-widetag
+                          (1+ bignum-digits-offset) nil)
+    (storew temp res bignum-digits-offset other-pointer-lowtag))
+  (lisp-return lra lip :offset 2)
 
   DO-STATIC-FUN
   (inst lw lip null-tn (static-fun-offset 'two-arg--))
   (inst li nargs (fixnumize 2))
-  (inst move ocfp cfp-tn)
+  (move ocfp cfp-tn)
   (inst j lip)
-  (inst move cfp-tn csp-tn))
+  (move cfp-tn csp-tn t))
+
+
+
+;;;; Multiplication
 
 
 (define-assembly-routine (generic-*
-			  (:cost 25)
-			  (:return-style :full-call)
-			  (:translate *)
-			  (:policy :safe)
-			  (:save-p t))
-			 ((:arg x (descriptor-reg any-reg) a0-offset)
-			  (:arg y (descriptor-reg any-reg) a1-offset)
-
-			  (:res res (descriptor-reg any-reg) a0-offset)
-
-			  (:temp temp non-descriptor-reg nl0-offset)
-			  (:temp lo non-descriptor-reg nl1-offset)
-			  (:temp hi non-descriptor-reg nl2-offset)
-			  (:temp pa-flag non-descriptor-reg nl4-offset)
-			  (:temp lip interior-reg lip-offset)
-			  (:temp lra descriptor-reg lra-offset)
-			  (:temp nargs any-reg nargs-offset)
-			  (:temp ocfp any-reg ocfp-offset))
+                          (:cost 25)
+                          (:return-style :full-call)
+                          (:translate *)
+                          (:policy :safe)
+                          (:save-p t))
+                         ((:arg x (descriptor-reg any-reg) a0-offset)
+                          (:arg y (descriptor-reg any-reg) a1-offset)
+
+                          (:res res (descriptor-reg any-reg) a0-offset)
+
+                          (:temp temp non-descriptor-reg nl0-offset)
+                          (:temp lo non-descriptor-reg nl1-offset)
+                          (:temp hi non-descriptor-reg nl2-offset)
+                          (:temp pa-flag non-descriptor-reg nl4-offset)
+                          (:temp lra descriptor-reg lra-offset)
+                          (:temp lip interior-reg lip-offset)
+                          (:temp nargs any-reg nargs-offset)
+                          (:temp ocfp any-reg ocfp-offset))
   ;; If either arg is not a fixnum, call the static function.
-  (inst and temp x 3)
-  (inst bne temp DO-STATIC-FUN)
-  (inst and temp y 3)
+  (inst or temp x y)
+  (inst and temp fixnum-tag-mask)
   (inst bne temp DO-STATIC-FUN)
-  (inst nop)
-
   ;; Remove the tag from one arg so that the result will have the correct
   ;; fixnum tag.
-  (inst sra temp x 2)
+  (inst sra temp x n-fixnum-tag-bits)
   (inst mult temp y)
   (inst mflo res)
   (inst mfhi hi)
   ;; Check to see if the result will fit in a fixnum.  (I.e. the high word
   ;; is just 32 copies of the sign bit of the low word).
   (inst sra temp res 31)
-  (inst xor temp hi)
-  (inst beq temp DONE)
+  (inst bne temp hi DO-BIGNUM)
+  (inst srl lo res n-fixnum-tag-bits)
+  (lisp-return lra lip :offset 2)
+
+  DO-BIGNUM
   ;; Shift the double word hi:res down two bits into hi:low to get rid of the
   ;; fixnum tag.
-  (inst srl lo res 2)
-  (inst sll temp hi 30)
+  (inst sll temp hi (- n-word-bits n-fixnum-tag-bits))
   (inst or lo temp)
-  (inst sra hi 2)
+  (inst sra hi n-fixnum-tag-bits)
 
   ;; Do we need one word or two?  Assume two.
   (inst sra temp lo 31)
-  (inst xor temp hi)
-  (inst bne temp two-words)
+  (inst bne temp hi TWO-WORDS)
   ;; Assume a two word header.
   (inst li temp (logior (ash 2 n-widetag-bits) bignum-widetag))
 
@@ -130,13 +178,9 @@
   (pseudo-atomic (pa-flag :extra (pad-data-block (+ 1 bignum-digits-offset)))
     (inst or res alloc-tn other-pointer-lowtag)
     (storew temp res 0 other-pointer-lowtag))
-
   (storew lo res bignum-digits-offset other-pointer-lowtag)
-
-  ;; Out of here
   (lisp-return lra lip :offset 2)
 
-
   TWO-WORDS
   (pseudo-atomic (pa-flag :extra (pad-data-block (+ 2 bignum-digits-offset)))
     (inst or res alloc-tn other-pointer-lowtag)
@@ -144,19 +188,108 @@
 
   (storew lo res bignum-digits-offset other-pointer-lowtag)
   (storew hi res (1+ bignum-digits-offset) other-pointer-lowtag)
-
-  ;; Out of here
   (lisp-return lra lip :offset 2)
 
-
   DO-STATIC-FUN
   (inst lw lip null-tn (static-fun-offset 'two-arg-*))
   (inst li nargs (fixnumize 2))
-  (inst move ocfp cfp-tn)
+  (move ocfp cfp-tn)
   (inst j lip)
-  (inst move cfp-tn csp-tn)
+  (move cfp-tn csp-tn t))
 
-  DONE)
+
+(macrolet
+    ((frob (name note cost type sc signed-p)
+       `(define-assembly-routine (,name
+                                  (:note ,note)
+                                  (:cost ,cost)
+                                  (:translate *)
+                                  (:policy :fast-safe)
+                                  (:arg-types ,type ,type)
+                                  (:result-types ,type))
+                                 ((:arg x ,sc nl0-offset)
+                                  (:arg y ,sc nl1-offset)
+                                  (:res res ,sc nl0-offset))
+          ,@(when (eq type 'tagged-num)
+              `((inst sra x 2)))
+          (inst ,(if signed-p 'mult 'multu) x y)
+          (inst mflo res))))
+  (frob unsigned-* "unsigned *" 40 unsigned-num unsigned-reg nil)
+  (frob signed-* "signed *" 41 signed-num signed-reg t)
+  (frob fixnum-* "fixnum *" 30 tagged-num any-reg t))
+
+
+
+;;;; Division.
+
+
+(define-assembly-routine (positive-fixnum-truncate
+                          (:note "unsigned fixnum truncate")
+                          (:cost 45)
+                          (:translate truncate)
+                          (:policy :fast-safe)
+                          (:arg-types positive-fixnum positive-fixnum)
+                          (:result-types positive-fixnum positive-fixnum))
+                         ((:arg dividend any-reg nl0-offset)
+                          (:arg divisor any-reg nl1-offset)
+
+                          (:res quo any-reg nl2-offset)
+                          (:res rem any-reg nl3-offset))
+  (let ((error (generate-error-code nil division-by-zero-error
+                                    dividend divisor)))
+    (inst beq divisor error)
+    (inst nop))
+
+    (inst divu dividend divisor)
+    (inst mflo quo)
+    (inst mfhi rem)
+    (inst sll quo 2))
+
+
+(define-assembly-routine (fixnum-truncate
+                          (:note "fixnum truncate")
+                          (:cost 50)
+                          (:policy :fast-safe)
+                          (:translate truncate)
+                          (:arg-types tagged-num tagged-num)
+                          (:result-types tagged-num tagged-num))
+                         ((:arg dividend any-reg nl0-offset)
+                          (:arg divisor any-reg nl1-offset)
+
+                          (:res quo any-reg nl2-offset)
+                          (:res rem any-reg nl3-offset))
+  (let ((error (generate-error-code nil division-by-zero-error
+                                    dividend divisor)))
+    (inst beq divisor error)
+    (inst nop))
+
+    (inst div dividend divisor)
+    (inst mflo quo)
+    (inst mfhi rem)
+    (inst sll quo 2))
+
+
+(define-assembly-routine (signed-truncate
+                          (:note "(signed-byte 32) truncate")
+                          (:cost 60)
+                          (:policy :fast-safe)
+                          (:translate truncate)
+                          (:arg-types signed-num signed-num)
+                          (:result-types signed-num signed-num))
+
+                         ((:arg dividend signed-reg nl0-offset)
+                          (:arg divisor signed-reg nl1-offset)
+
+                          (:res quo signed-reg nl2-offset)
+                          (:res rem signed-reg nl3-offset))
+  (let ((error (generate-error-code nil division-by-zero-error
+                                    dividend divisor)))
+    (inst beq divisor error)
+    (inst nop))
+
+    (inst div dividend divisor)
+    (inst mflo quo)
+    (inst mfhi rem))
 
 
 
@@ -165,148 +298,152 @@
 (macrolet
     ((define-cond-assem-rtn (name translate static-fn cmp not-p)
        `(define-assembly-routine (,name
-				  (:cost 10)
-				  (:return-style :full-call)
-				  (:policy :safe)
-				  (:translate ,translate)
-				  (:save-p t))
-				 ((:arg x (descriptor-reg any-reg) a0-offset)
-				  (:arg y (descriptor-reg any-reg) a1-offset)
-				  
-				  (:res res descriptor-reg a0-offset)
-				  
-				  (:temp temp non-descriptor-reg nl0-offset)
-				  (:temp lip interior-reg lip-offset)
-				  (:temp nargs any-reg nargs-offset)
-				  (:temp ocfp any-reg ocfp-offset))
-	  (inst and temp x 3)
-	  (inst bne temp DO-STATIC-FN)
-	  (inst and temp y 3)
-	  (inst beq temp DO-COMPARE)
-	  ,cmp
-	  
-	  DO-STATIC-FN
-	  (inst lw lip null-tn (static-fun-offset ',static-fn))
-	  (inst li nargs (fixnumize 2))
-	  (inst move ocfp cfp-tn)
-	  (inst j lip)
-	  (inst move cfp-tn csp-tn)
-	  
-	  DO-COMPARE
-	  (inst ,(if not-p 'bne 'beq) temp done)
-	  (inst move res null-tn)
-	  (load-symbol res t)
-	  DONE)))
-
-  (define-cond-assem-rtn generic-< < two-arg-< (inst slt temp x y) nil)
-  (define-cond-assem-rtn generic-> > two-arg-> (inst slt temp y x) nil))
+                                  (:cost 10)
+                                  (:return-style :full-call)
+                                  (:policy :safe)
+                                  (:translate ,translate)
+                                  (:save-p t))
+                                 ((:arg x (descriptor-reg any-reg) a0-offset)
+                                  (:arg y (descriptor-reg any-reg) a1-offset)
+
+                                  (:res res descriptor-reg a0-offset)
+
+                                  (:temp temp non-descriptor-reg nl0-offset)
+                                  (:temp lra descriptor-reg lra-offset)
+                                  (:temp lip interior-reg lip-offset)
+                                  (:temp nargs any-reg nargs-offset)
+                                  (:temp ocfp any-reg ocfp-offset))
+          (inst or temp x y)
+          (inst and temp fixnum-tag-mask)
+          (inst bne temp DO-STATIC-FUN)
+          ,cmp
+
+          (inst ,(if not-p 'beq 'bne) temp DONE)
+          (move res null-tn t)
+          (load-symbol res t)
+
+          DONE
+          (lisp-return lra lip :offset 2)
+
+          DO-STATIC-FUN
+          (inst lw lip null-tn (static-fun-offset ',static-fn))
+          (inst li nargs (fixnumize 2))
+          (move ocfp cfp-tn)
+          (inst j lip)
+          (move cfp-tn csp-tn t))))
+
+  (define-cond-assem-rtn generic-< < two-arg-< (inst slt temp x y) t)
+  (define-cond-assem-rtn generic-<= <= two-arg-<= (inst slt temp x y) nil)
+  (define-cond-assem-rtn generic-> > two-arg-> (inst slt temp y x) t)
+  (define-cond-assem-rtn generic->= >= two-arg->= (inst slt temp y x) nil))
 
 
 (define-assembly-routine (generic-eql
-			  (:cost 10)
-			  (:return-style :full-call)
-			  (:policy :safe)
-			  (:translate eql)
-			  (:save-p t))
-			 ((:arg x (descriptor-reg any-reg) a0-offset)
-			  (:arg y (descriptor-reg any-reg) a1-offset)
-			  
-			  (:res res descriptor-reg a0-offset)
-			  
-			  (:temp temp non-descriptor-reg nl0-offset)
-			  (:temp lip interior-reg lip-offset)
-			  (:temp lra descriptor-reg lra-offset)
-			  (:temp nargs any-reg nargs-offset)
-			  (:temp ocfp any-reg ocfp-offset))
+                          (:cost 10)
+                          (:return-style :full-call)
+                          (:policy :safe)
+                          (:translate eql)
+                          (:save-p t))
+                         ((:arg x (descriptor-reg any-reg) a0-offset)
+                          (:arg y (descriptor-reg any-reg) a1-offset)
+
+                          (:res res descriptor-reg a0-offset)
+
+                          (:temp temp non-descriptor-reg nl0-offset)
+                          (:temp lra descriptor-reg lra-offset)
+                          (:temp lip interior-reg lip-offset)
+                          (:temp nargs any-reg nargs-offset)
+                          (:temp ocfp any-reg ocfp-offset))
   (inst beq x y RETURN-T)
-  (inst and temp x 3)
-  (inst beq temp RETURN-NIL)
-  (inst and temp y 3)
-  (inst bne temp DO-STATIC-FN)
+  (inst or temp x y)
+  (inst and temp fixnum-tag-mask)
+  (inst bne temp DO-STATIC-FUN)
   (inst nop)
 
-  RETURN-NIL
-  (inst move res null-tn)
+  (inst bne x y DONE)
+  (move res null-tn t)
+
+  RETURN-T
+  (load-symbol res t)
+
+  DONE
   (lisp-return lra lip :offset 2)
 
-  DO-STATIC-FN
+  DO-STATIC-FUN
   (inst lw lip null-tn (static-fun-offset 'eql))
   (inst li nargs (fixnumize 2))
-  (inst move ocfp cfp-tn)
+  (move ocfp cfp-tn)
   (inst j lip)
-  (inst move cfp-tn csp-tn)
+  (move cfp-tn csp-tn t))
 
-  RETURN-T
-  (load-symbol res t))
 
 (define-assembly-routine (generic-=
-			  (:cost 10)
-			  (:return-style :full-call)
-			  (:policy :safe)
-			  (:translate =)
-			  (:save-p t))
-			 ((:arg x (descriptor-reg any-reg) a0-offset)
-			  (:arg y (descriptor-reg any-reg) a1-offset)
-			  
-			  (:res res descriptor-reg a0-offset)
-			  
-			  (:temp temp non-descriptor-reg nl0-offset)
-			  (:temp lip interior-reg lip-offset)
-			  (:temp lra descriptor-reg lra-offset)
-			  (:temp nargs any-reg nargs-offset)
-			  (:temp ocfp any-reg ocfp-offset))
-  (inst and temp x 3)
-  (inst bne temp DO-STATIC-FN)
-  (inst and temp y 3)
-  (inst bne temp DO-STATIC-FN)
+                          (:cost 10)
+                          (:return-style :full-call)
+                          (:policy :safe)
+                          (:translate =)
+                          (:save-p t))
+                         ((:arg x (descriptor-reg any-reg) a0-offset)
+                          (:arg y (descriptor-reg any-reg) a1-offset)
+
+                          (:res res descriptor-reg a0-offset)
+
+                          (:temp temp non-descriptor-reg nl0-offset)
+                          (:temp lra descriptor-reg lra-offset)
+                          (:temp lip interior-reg lip-offset)
+                          (:temp nargs any-reg nargs-offset)
+                          (:temp ocfp any-reg ocfp-offset))
+  (inst or temp x y)
+  (inst and temp fixnum-tag-mask)
+  (inst bne temp DO-STATIC-FUN)
   (inst nop)
-  (inst beq x y RETURN-T)
 
-  (inst move res null-tn)
+  (inst bne x y DONE)
+  (move res null-tn t)
+  (load-symbol res t)
+
+  DONE
   (lisp-return lra lip :offset 2)
 
-  DO-STATIC-FN
+  DO-STATIC-FUN
   (inst lw lip null-tn (static-fun-offset 'two-arg-=))
   (inst li nargs (fixnumize 2))
-  (inst move ocfp cfp-tn)
+  (move ocfp cfp-tn)
   (inst j lip)
-  (inst move cfp-tn csp-tn)
+  (move cfp-tn csp-tn t))
 
-  RETURN-T
-  (load-symbol res t))
 
 (define-assembly-routine (generic-/=
-			  (:cost 10)
-			  (:return-style :full-call)
-			  (:policy :safe)
-			  (:translate /=)
-			  (:save-p t))
-			 ((:arg x (descriptor-reg any-reg) a0-offset)
-			  (:arg y (descriptor-reg any-reg) a1-offset)
-			  
-			  (:res res descriptor-reg a0-offset)
-			  
-			  (:temp temp non-descriptor-reg nl0-offset)
-			  (:temp lip interior-reg lip-offset)
-			  (:temp lra descriptor-reg lra-offset)
-			  (:temp nargs any-reg nargs-offset)
-			  (:temp ocfp any-reg ocfp-offset))
-  (inst and temp x 3)
-  (inst bne temp DO-STATIC-FN)
-  (inst and temp y 3)
-  (inst bne temp DO-STATIC-FN)
+                          (:cost 10)
+                          (:return-style :full-call)
+                          (:policy :safe)
+                          (:translate /=)
+                          (:save-p t))
+                         ((:arg x (descriptor-reg any-reg) a0-offset)
+                          (:arg y (descriptor-reg any-reg) a1-offset)
+
+                          (:res res descriptor-reg a0-offset)
+
+                          (:temp temp non-descriptor-reg nl0-offset)
+                          (:temp lra descriptor-reg lra-offset)
+                          (:temp lip interior-reg lip-offset)
+                          (:temp nargs any-reg nargs-offset)
+                          (:temp ocfp any-reg ocfp-offset))
+  (inst or temp x y)
+  (inst and temp fixnum-tag-mask)
+  (inst bne temp DO-STATIC-FUN)
   (inst nop)
-  (inst beq x y RETURN-NIL)
 
+  (inst beq x y DONE)
+  (move res null-tn t)
   (load-symbol res t)
+
+  DONE
   (lisp-return lra lip :offset 2)
 
-  DO-STATIC-FN
-  (inst lw lip null-tn (static-fun-offset 'two-arg-=))
+  DO-STATIC-FUN
+  (inst lw lip null-tn (static-fun-offset 'two-arg-/=))
   (inst li nargs (fixnumize 2))
-  (inst move ocfp cfp-tn)
+  (move ocfp cfp-tn)
   (inst j lip)
-  (inst move cfp-tn csp-tn)
-
-  RETURN-NIL
-  (inst move res null-tn))
+  (move cfp-tn csp-tn t))