diff --git a/benchmarks/results.Larceny-r6rs b/benchmarks/results.Larceny-r6rs
index b847086..1175536 100644
--- a/benchmarks/results.Larceny-r6rs
+++ b/benchmarks/results.Larceny-r6rs
@@ -1170,3 +1170,235 @@ Words allocated: 201324942
 Words reclaimed: 0
 Elapsed time...: 4280 ms (User: 3750 ms; System: 529 ms)
 Elapsed GC time: 2443 ms (CPU: 2444 in 768 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 18:30:18 EST 2007 under Darwin Vesuvius.local 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing peval under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 34340444
+Words reclaimed: 0
+Elapsed time...: 1255 ms (User: 1248 ms; System: 7 ms)
+Elapsed GC time: 55 ms (CPU: 60 in 131 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 18:43:05 EST 2007 under Darwin Vesuvius.local 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing peval under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 34340444
+Words reclaimed: 0
+Elapsed time...: 1256 ms (User: 1249 ms; System: 7 ms)
+Elapsed GC time: 60 ms (CPU: 65 in 131 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 18:44:20 EST 2007 under Darwin Vesuvius.local 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing paraffins under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 201324942
+Words reclaimed: 0
+Elapsed time...: 4278 ms (User: 3750 ms; System: 528 ms)
+Elapsed GC time: 2445 ms (CPU: 2437 in 768 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 18:46:28 EST 2007 under Darwin Vesuvius.local 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing compiler under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> WARNING from macro expander:
+Redefining 
+bound?
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 18:47:54 EST 2007 under Darwin Vesuvius.local 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing slatex under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 4194150
+Words reclaimed: 0
+Elapsed time...: 1843 ms (User: 532 ms; System: 777 ms)
+Elapsed GC time: 15 ms (CPU: 8 in 16 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 18:49:52 EST 2007 under Darwin Vesuvius.local 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing scheme under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 29621860
+Words reclaimed: 0
+Elapsed time...: 1193 ms (User: 1190 ms; System: 3 ms)
+Elapsed GC time: 46 ms (CPU: 45 in 113 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 18:50:38 EST 2007 under Darwin Vesuvius.local 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing earley under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 123206268
+Words reclaimed: 0
+Elapsed time...: 2023 ms (User: 1932 ms; System: 91 ms)
+Elapsed GC time: 580 ms (CPU: 582 in 470 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 22:59:25 EST 2007 under Darwin adsl-68-251-150-42.dsl.bltnin.ameritech.net 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing dderiv under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 244055776
+Words reclaimed: 0
+Elapsed time...: 1905 ms (User: 1893 ms; System: 11 ms)
+Elapsed GC time: 333 ms (CPU: 332 in 931 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 23:00:51 EST 2007 under Darwin adsl-68-251-150-42.dsl.bltnin.ameritech.net 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing puzzle under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 8126378
+Words reclaimed: 0
+Elapsed time...: 1953 ms (User: 1807 ms; System: 144 ms)
+Elapsed GC time: 17 ms (CPU: 10 in 31 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 23:02:15 EST 2007 under Darwin adsl-68-251-150-42.dsl.bltnin.ameritech.net 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing parsing under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 100923902
+Words reclaimed: 0
+Elapsed time...: 6587 ms (User: 6512 ms; System: 74 ms)
+Elapsed GC time: 295 ms (CPU: 295 in 385 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 23:30:51 EST 2007 under Darwin adsl-68-251-150-42.dsl.bltnin.ameritech.net 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing parsing under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 100923902
+Words reclaimed: 0
+Elapsed time...: 6584 ms (User: 6509 ms; System: 72 ms)
+Elapsed GC time: 296 ms (CPU: 287 in 385 collections.)
+
+****************************
+Benchmarking Larceny-r6rs on Mon Feb 19 23:32:41 EST 2007 under Darwin adsl-68-251-150-42.dsl.bltnin.ameritech.net 8.8.3 Darwin Kernel Version 8.8.3: Wed Oct 18 21:57:10 PDT 2006; root:xnu-792.15.4.obj~4/RELEASE_I386 i386 i386
+
+Testing parsing under Larceny-r6rs
+Compiling...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+> 
+Running...
+Larceny v0.93 "Deviated Prevert" (Nov 10 2006 04:27:45, precise:BSD Unix:unified)
+
+
+> 
+Words allocated: 100923902
+Words reclaimed: 0
+Elapsed time...: 6590 ms (User: 6512 ms; System: 75 ms)
+Elapsed GC time: 284 ms (CPU: 288 in 385 collections.)
diff --git a/benchmarks/sys/larceny/compiler.scm b/benchmarks/sys/larceny/compiler.scm
index ad1520c..79b01c9 100644
--- a/benchmarks/sys/larceny/compiler.scm
+++ b/benchmarks/sys/larceny/compiler.scm
@@ -560,6 +560,8 @@
 (define parsing-iters    1000)
 (define gcold-iters     10000)
 ;(define nbody-iters         1) ; nondeterministic (order of evaluation)
+
+
 ;(define integer->char ascii->char)
 ;(define char->integer char->ascii)
 
diff --git a/src/ikarus.boot b/src/ikarus.boot
index bba2855..6698924 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/libaltcogen.ss b/src/libaltcogen.ss
index 8ce839f..e3d9b09 100644
--- a/src/libaltcogen.ss
+++ b/src/libaltcogen.ss
@@ -198,6 +198,7 @@
       [top-level-value            v]
       [$symbol-value              v]
 
+      [$memq                     pv]
 
       [$record           vt]
       [$record/rtd?      p]
@@ -494,6 +495,26 @@
              (case (length rands)
                [(1) (P (car rands))]
                [else (make-seq (E x) (make-constant #t))])]
+            [($memq) 
+             (record-case (cadr rands)
+               [(constant ls)
+                (unless (list? ls) (error who "invalid call to $memq"))
+                (cond
+                  [(null? ls) 
+                   (make-seq (E (car rands)) (make-constant #f))]
+                  [else
+                   (let ([t (unique-var 'tmp)])
+                     (make-bind (list t) (list (V (car rands)))
+                        (let f ([ls ls])
+                          (cond
+                            [(null? (cdr ls)) 
+                             (make-primcall 'eq? (list t (make-constant (car ls))))]
+                            [else
+                             (make-conditional 
+                               (make-primcall 'eq? (list t (make-constant (car ls))))
+                               (make-constant #t)
+                               (f (cdr ls)))]))))])]
+               [else (Predicafy x)])]
             [(not)
              (make-conditional 
                (P (car rands)) 
@@ -567,6 +588,26 @@
          [(e) (make-seq (E x) (make-constant (void)))]
          [(pv)
           (case op
+            [($memq) 
+             (record-case (cadr rands)
+               [(constant ls)
+                (unless (list? ls) (error who "invalid call to $memq"))
+                (cond
+                  [(null? ls) 
+                   (make-seq (E (car rands)) (make-constant #f))]
+                  [else
+                   (let ([t (unique-var 'tmp)])
+                     (make-bind (list t) (list (V (car rands)))
+                        (let f ([ls ls])
+                          (cond
+                            [(null? ls) 
+                             (make-constant #f)]
+                            [else
+                             (make-conditional 
+                               (make-primcall 'eq? (list t (make-constant (car ls))))
+                               (make-constant ls)
+                               (f (cdr ls)))]))))])]
+               [else (make-funcall (make-primref '$memq) (map V rands))])]
             [(list*) 
              (case (length rands)
                [(0) (make-funcall (make-primref 'list*) '())]
@@ -1767,11 +1808,9 @@
     (cond
       [(null? nf*) ac]
       [else
-       (let ([t (unique-var 't)])
-         (do-bind (list t) (list (car v*))
-           (make-seq
-             (make-set (car nf*) t)
-             (do-bind-frmt* (cdr nf*) (cdr v*) ac))))]))
+       (make-seq
+         (V (car nf*) (car v*))
+         (do-bind-frmt* (cdr nf*) (cdr v*) ac))]))
   ;;;
   (define (handle-nontail-call rator rands value-dest call-targ)
     (let-values ([(reg-locs reg-args frm-args)
@@ -2466,6 +2505,11 @@
               [(nfv? d)
                (cond
                  [(not (mem-nfv? d ns)) (error who "dead nfv")]
+                 [(or (disp? s) (constant? s) (reg? s))
+                  (let ([ns (rem-nfv d ns)])
+                    (mark-nfv/vars-conf! d vs)
+                    (mark-nfv/frms-conf! d fs)
+                    (R s vs rs fs ns))]
                  [(var? s)
                   (let ([ns (rem-nfv d ns)]
                         [vs (rem-var s vs)])
@@ -2496,6 +2540,14 @@
                   (let ([rs (rem-reg d rs)])
                     (mark-reg/vars-conf! d vs)
                     (R s vs (set-add d rs) fs ns))])]
+              [(nfv? d) 
+               (cond
+                 [(not (mem-nfv? d ns)) (error who "dead nfv")]
+                 [else
+                  (let ([ns (rem-nfv d ns)])
+                    (mark-nfv/vars-conf! d vs)
+                    (mark-nfv/frms-conf! d fs)
+                    (R s vs rs fs (add-nfv d ns)))])]
               [else (error who "invalid op d ~s" (unparse x))])]
            [(idiv) 
             (mark-reg/vars-conf! eax vs)
diff --git a/src/libintelasm.ss b/src/libintelasm.ss
index 790a6d8..086f8fe 100644
--- a/src/libintelasm.ss
+++ b/src/libintelasm.ss
@@ -540,6 +540,8 @@
        (CODE #x29 (ModRM 3 src dst ac))]
       [(and (mem? src) (reg? dst))
        (CODErd #x2B dst src ac)]
+      [(and (imm? src) (mem? dst)) 
+       ((CODE/digit #x81 '/5) dst (IMM32 src ac))]
       [(and (reg? src) (mem? dst))
        ((CODE/digit #x29 src) dst ac)]
       [else (error who "invalid ~s" instr)])]