diff --git a/102keyboard.subx b/102keyboard.subx
index 0c8826e1..39788075 100644
--- a/102keyboard.subx
+++ b/102keyboard.subx
@@ -37,7 +37,7 @@ read-key:  # kbd: (addr keyboard) -> result/eax: byte
       # var next-key/eax: byte = *buffer-byte-addr
       8a/byte-> *ecx 0/r32/AL
       # if (next-key != 0) lock and remove from keyboard buffer
-      81 7/subop/compare %eax 0/imm32
+      3d/compare-eax-with 0/imm32
       {
         74/jump-if-= break/disp8
         fa/disable-interrupts
diff --git a/103grapheme.subx b/103grapheme.subx
index 1941d49b..269e3c02 100644
--- a/103grapheme.subx
+++ b/103grapheme.subx
@@ -45,7 +45,7 @@ draw-grapheme-on-real-screen:  # g: grapheme, x: int, y: int, color: int, backgr
       # var xcurr/eax: int = x*8 + 7
       8b/-> *(ebp+0xc) 0/r32/eax  # font-width - 1
       c1 4/subop/shift-left %eax 3/imm8
-      81 0/subop/add %eax 7/imm32
+      05/add-to-eax 7/imm32
       # var xmin/ecx: int = x*8
       8b/-> *(ebp+0xc) 1/r32/ecx
       c1 4/subop/shift-left %ecx 3/imm8
diff --git a/311decimal-int.subx b/311decimal-int.subx
index f7c108dd..b736ba03 100644
--- a/311decimal-int.subx
+++ b/311decimal-int.subx
@@ -66,7 +66,7 @@ parse-decimal-int-from-stream:  # in: (addr stream byte) -> result/eax: int
       4a/decrement-edx
       # if it's a newline, break
       8a/byte-> *edx 0/r32/eax
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       3d/compare-eax-and 0xa/imm32/newline
       74/jump-if-= break/disp8
       # not a newline, so restore it
diff --git a/315stack-debug.subx b/315stack-debug.subx
index d8bc2e0f..ef86fc09 100644
--- a/315stack-debug.subx
+++ b/315stack-debug.subx
@@ -10,7 +10,7 @@ check-stack:
     50/push-eax
     #
     89/<- %eax 4/r32/esp
-    81 7/subop/compare %eax 0x01000000/imm32
+    3d/compare-eax-and 0x01000000/imm32
     {
       7f/jump-if-> break/disp8
       (abort "stack overflow")
diff --git a/boot.subx b/boot.subx
index afe826ca..424e9627 100644
--- a/boot.subx
+++ b/boot.subx
@@ -1520,7 +1520,7 @@ wait-for-ack-from-mouse:
   50/push-eax
   {
     (read-keyboard-controller-data)  # => eax
-    81 7/subop/compare %eax 0xfa/imm32
+    3d/compare-eax-with 0xfa/imm32
     75/jump-if-!= loop/disp8
   }
 $wait-for-ack-from-mouse:end:
diff --git a/linux/304screen.subx b/linux/304screen.subx
index 8a8df8f9..0b24fdbf 100644
--- a/linux/304screen.subx
+++ b/linux/304screen.subx
@@ -56,7 +56,7 @@ real-screen-size:  # -> nrows/eax: int, ncols/ecx: int
     e8/call syscall_ioctl/disp32
     # some bitworking to extract 2 16-bit shorts
     8b/-> *esi 0/r32/eax
-    81 4/subop/and %eax 0xffff/imm32
+    25/and-eax-with 0xffff/imm32
     8b/-> *esi 1/r32/ecx
     c1/shift 5/subop/logical-right %ecx 0x10/imm8
 $real-screen-size:end:
diff --git a/linux/311decimal-int.subx b/linux/311decimal-int.subx
index 80b60c26..0e02557a 100644
--- a/linux/311decimal-int.subx
+++ b/linux/311decimal-int.subx
@@ -66,7 +66,7 @@ parse-decimal-int-from-stream:  # in: (addr stream byte) -> result/eax: int
       4a/decrement-edx
       # if it's a newline, break
       8a/byte-> *edx 0/r32/eax
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       3d/compare-eax-and 0xa/imm32/newline
       74/jump-if-= break/disp8
       # not a newline, so restore it
diff --git a/linux/braces b/linux/braces
index 05613283..573a66be 100755
Binary files a/linux/braces and b/linux/braces differ
diff --git a/linux/braces.subx b/linux/braces.subx
index e09229a9..58e3ec59 100644
--- a/linux/braces.subx
+++ b/linux/braces.subx
@@ -152,7 +152,7 @@ $subx-braces:check-for-curly-open:
     # . eax = line->data[line->read]
     8b/-> *(ecx+4) 0/r32/eax
     8a/copy-byte *(ecx+eax+0xc) 0/r32/AL
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # . if (eax != '{') continue
     3d/compare-eax-and 0x7b/imm32/open-curly
     0f 85/jump-if-!= $subx-braces:check-for-curly-closed/disp32
@@ -192,7 +192,7 @@ $subx-braces:check-for-comment:
     # . eax = *word-slice->start
     8b/-> *edi 0/r32/eax
     8a/copy-byte *eax 0/r32/AL
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # . if (eax == '#') continue
     3d/compare-eax-and 0x23/imm32/hash
     74/jump-if-= $subx-braces:word-loop/disp8
diff --git a/linux/calls b/linux/calls
index 344f8355..f92f9d24 100755
Binary files a/linux/calls and b/linux/calls differ
diff --git a/linux/calls.subx b/linux/calls.subx
index cbe327d3..2c962e77 100644
--- a/linux/calls.subx
+++ b/linux/calls.subx
@@ -428,7 +428,7 @@ $emit-call:push-loop:
     # . . eax = *(curr->start+4)
     8b/-> *ecx 0/r32/eax
     8a/copy-byte *(eax+4) 0/r32/eax
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # . . push args
     50/push-eax
     ff 6/subop/push *(ebp+8)
@@ -451,7 +451,7 @@ $emit-call:push-int:
     8b/-> *ecx 0/r32/eax
     # . var c/eax: byte = *eax
     8b/-> *eax 0/r32/eax
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # . if (c == '%') goto push-rm32
     3d/compare-eax-and 0x25/imm32/percent
     74/jump-if-= $emit-call:push-rm32/disp8
@@ -1361,7 +1361,7 @@ test-next-word-string-or-expression-without-metadata:
     68/push 0xe/imm32
     # . . push slice->start - _test-input-stream
     8b/-> *ecx 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1374,7 +1374,7 @@ test-next-word-string-or-expression-without-metadata:
     68/push 0x10/imm32
     # . . push slice->end - _test-input-stream
     8b/-> *(ecx+4) 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1434,7 +1434,7 @@ test-next-word-string-or-expression-without-metadata-returns-whole-comment:
     68/push 0xe/imm32
     # . . push slice->start - _test-input-stream
     8b/-> *ecx 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1447,7 +1447,7 @@ test-next-word-string-or-expression-without-metadata-returns-whole-comment:
     68/push 0x11/imm32
     # . . push slice->end - _test-input-stream
     8b/-> *(ecx+4) 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1497,7 +1497,7 @@ test-next-word-string-or-expression-without-metadata-returns-string-literal:
     68/push 0xd/imm32
     # . . push slice->start - _test-input-stream
     8b/-> *ecx 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1510,7 +1510,7 @@ test-next-word-string-or-expression-without-metadata-returns-string-literal:
     68/push 0x12/imm32
     # . . push slice->end - _test-input-stream
     8b/-> *(ecx+4) 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1560,7 +1560,7 @@ test-next-word-string-or-expression-without-metadata-returns-string-with-escapes
     68/push 0xd/imm32
     # . . push slice->start - _test-input-stream
     8b/-> *ecx 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1573,7 +1573,7 @@ test-next-word-string-or-expression-without-metadata-returns-string-with-escapes
     68/push 0x13/imm32
     # . . push slice->end - _test-input-stream
     8b/-> *(ecx+4) 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1623,7 +1623,7 @@ test-next-word-string-or-expression-without-metadata-returns-whole-expression:
     68/push 0xd/imm32
     # . . push slice->start - _test-input-stream
     8b/-> *ecx 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1636,7 +1636,7 @@ test-next-word-string-or-expression-without-metadata-returns-whole-expression:
     68/push 0x13/imm32
     # . . push slice->end - _test-input-stream
     8b/-> *(ecx+4) 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1851,7 +1851,7 @@ test-next-word-string-or-expression-without-metadata-stops-at-close-paren:
     68/push 0xd/imm32
     # . . push slice->start - _test-input-stream
     8b/-> *ecx 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
@@ -1864,7 +1864,7 @@ test-next-word-string-or-expression-without-metadata-stops-at-close-paren:
     68/push 0x10/imm32
     # . . push slice->end - _test-input-stream
     8b/-> *(ecx+4) 0/r32/eax
-    81 5/subop/subtract %eax _test-input-stream/imm32
+    2d/subtract-from-eax _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call check-ints-equal/disp32
diff --git a/linux/labels_baremetal b/linux/labels_baremetal
index 4478449b..de2749d8 100755
Binary files a/linux/labels_baremetal and b/linux/labels_baremetal differ
diff --git a/linux/labels_baremetal.subx b/linux/labels_baremetal.subx
index 9dce9bbf..e4a29b62 100644
--- a/linux/labels_baremetal.subx
+++ b/linux/labels_baremetal.subx
@@ -2075,7 +2075,7 @@ $far-jump-or-call?:check-second-word:
     8b/copy                         0/mod/indirect  2/rm32/edx    .           .             .           0/r32/eax   .               .                 # copy *edx to eax
     # . c/eax = *start
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     # . if (eax != '8') return
     3d/compare-eax-and  0x38/imm32/8
     75/jump-if-!=  $far-jump-or-call?:end/disp8
diff --git a/linux/mu b/linux/mu
index 2508cda4..75d696b2 100755
Binary files a/linux/mu and b/linux/mu differ
diff --git a/linux/mu.subx b/linux/mu.subx
index 93065326..7c6f46c3 100644
--- a/linux/mu.subx
+++ b/linux/mu.subx
@@ -15807,7 +15807,7 @@ $parse-mu:line-loop:
       # . eax = *word-slice->start
       8b/-> *edx 0/r32/eax
       8a/copy-byte *eax 0/r32/AL
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       # . if (eax == '#') continue
       3d/compare-eax-and 0x23/imm32/hash
       0f 84/jump-if-= loop/disp32
@@ -16619,7 +16619,7 @@ type-tree-contains?:  # t: (addr type-tree), n: type-id -> result/eax: boolean
       8b/-> *(ebp+0xc) 1/r32/ecx
       39/compare *(eax+4) 1/r32/ecx  # Type-tree-value
       0f 94/set-if-= %al
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       eb/jump $type-tree-contains?:end/disp8
     }
     # if t->left contains n, return true
@@ -17094,7 +17094,7 @@ float-register?:  # r: (addr array byte) -> result/eax: boolean
     (get Mu-registers-unique *(ebp+8) 0xc "Mu-registers-unique")  # => eax
     81 7/subop/compare *eax 8/imm32/start-of-floating-point-registers
     0f 9d/set-if->= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $float-register?:end:
     # . epilogue
     89/<- %esp 5/r32/ebp
@@ -17179,7 +17179,7 @@ $parse-type:check-for-int:
         # var tmp/eax: byte = *s->slice
         8b/-> *ecx 0/r32/eax
         8a/copy-byte *eax 0/r32/AL
-        81 4/subop/and %eax 0xff/imm32
+        25/and-eax-with 0xff/imm32
         # TODO: raise an error on `var x: (array int a)`
         (decimal-digit? %eax)  # => eax
         3d/compare-eax-and 0/imm32/false
@@ -17202,7 +17202,7 @@ $parse-type:check-for-type-parameter:
         # var tmp/eax: byte = *s->slice
         8b/-> *ecx 0/r32/eax
         8a/copy-byte *eax 0/r32/AL
-        81 4/subop/and %eax 0xff/imm32
+        25/and-eax-with 0xff/imm32
         # if (tmp != '_') break
         3d/compare-eax-and 0x5f/imm32/_
         75/jump-if-!= break/disp8
@@ -17800,7 +17800,7 @@ identifier?:  # in: (addr slice) -> result/eax: boolean
     8b/-> *(ebp+8) 0/r32/eax
     8b/-> *eax 0/r32/eax
     8a/copy-byte *eax 0/r32/AL
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # if (c == '$') return true
     3d/compare-eax-and 0x24/imm32/$
     74/jump-if-= $identifier?:true/disp8
@@ -18213,7 +18213,7 @@ $parse-mu-block:line-loop:
       # . eax = *word-slice->start
       8b/-> *edx 0/r32/eax
       8a/copy-byte *eax 0/r32/AL
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       # . if (eax == '#') continue
       3d/compare-eax-and 0x23/imm32/hash
       0f 84/jump-if-= loop/disp32
@@ -18249,7 +18249,7 @@ $parse-mu-block:check-for-named-block:
         8b/-> *(edx+4) 0/r32/eax
         48/decrement-eax
         8a/copy-byte *eax 0/r32/AL
-        81 4/subop/and %eax 0xff/imm32
+        25/and-eax-with 0xff/imm32
         # . if (eax != ':') break
         3d/compare-eax-and 0x3a/imm32/colon
         0f 85/jump-if-!= break/disp32
@@ -18417,7 +18417,7 @@ check-no-tokens-left:  # line: (addr stream byte)
     # . eax = *s->start
     8b/-> *edx 0/r32/eax
     8a/copy-byte *eax 0/r32/AL
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # . if (eax == '#') continue
     3d/compare-eax-and 0x23/imm32/hash
     74/jump-if-= $check-no-tokens-left:end/disp8
@@ -18823,7 +18823,7 @@ $parse-mu-stmt:read-outputs:
         # if slice-starts-with?(name, "*") abort
         8b/-> *ecx 0/r32/eax  # Slice-start
         8a/copy-byte *eax 0/r32/AL
-        81 4/subop/and %eax 0xff/imm32
+        25/and-eax-with 0xff/imm32
         3d/compare-eax-and 0x2a/imm32/asterisk
         0f 84/jump-if-= $parse-mu-stmt:error-output-dereferenced/disp32
         # assert(identifier?(name))
@@ -18953,7 +18953,7 @@ $add-operation-and-inputs-to-stmt:read-inouts:
       # if (slice-starts-with?(name, '*')) ++name->start and set is-deref?
       8b/-> *ecx 0/r32/eax  # Slice-start
       8a/copy-byte *eax 0/r32/AL
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       3d/compare-eax-and 0x2a/imm32/asterisk
       {
         75/jump-if-!= break/disp8
@@ -19067,7 +19067,7 @@ stmt-has-outputs?:  # line: (addr stream byte) -> result/eax: boolean
       # . eax = *word-slice->start
       8b/-> *ecx 0/r32/eax
       8a/copy-byte *eax 0/r32/AL
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       # . if (eax == '#') break
       3d/compare-eax-and 0x23/imm32/hash
       b8/copy-to-eax 0/imm32/false/result  # restore result (if we're here it's still false)
@@ -20255,7 +20255,7 @@ container?:  # t: type-id -> result/eax: boolean
     c1/shift 4/subop/left %eax 2/imm8
     3b/compare 0/r32/eax *Primitive-type-ids
     0f 9d/set-if->= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $container?:end:
     # . epilogue
     89/<- %esp 5/r32/ebp
@@ -26520,7 +26520,7 @@ $type-component-match?:is-atom:
       8b/-> *(ecx+4) 0/r32/eax  # Type-tree-value
       39/compare *(edx+4) 0/r32/eax  # Type-tree-value
       0f 94/set-if-= %al
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       e9/jump $type-component-match?:end/disp32
     }
 $type-component-match?:check-left:
@@ -26687,7 +26687,7 @@ mu-array?:  # t: (addr type-tree) -> result/eax: boolean
     # return t->left->value == array
     81 7/subop/compare *(eax+4) 3/imm32/array-type-id  # Type-tree-value
     0f 94/set-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     eb/jump $mu-array?:end/disp8
 $mu-array?:return-false:
     b8/copy-to-eax 0/imm32/false
@@ -26752,7 +26752,7 @@ mu-stream?:  # t: (addr type-tree) -> result/eax: boolean
     # return t->left->value == stream
     81 7/subop/compare *(eax+4) 0xb/imm32/stream-type-id  # Type-tree-value
     0f 94/set-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     eb/jump $mu-stream?:end/disp8
 $mu-stream?:return-false:
     b8/copy-to-eax 0/imm32/false
@@ -26941,7 +26941,7 @@ $type-equal?:is-atom:
       8b/-> *(ecx+4) 0/r32/eax  # Type-tree-value
       39/compare *(edx+4) 0/r32/eax  # Type-tree-value
       0f 94/set-if-= %al
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       e9/jump $type-equal?:end/disp32
     }
 $type-equal?:check-left:
@@ -27459,7 +27459,7 @@ $emit-outputs:loop:
       89/<- %ecx 0/r32/eax
       # if curr-output-register starts with "x", emit a floating-point copy
       8a/copy-byte *(ecx+4) 0/r32/AL
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       3d/compare-eax-and 0x78/imm32/x
       {
         75/jump-if-!= break/disp8
@@ -27905,7 +27905,7 @@ emit-push-register:  # out: (addr buffered-file), reg: (addr array byte)
     8b/-> *(ebp+0xc) 0/r32/eax
     # var prefix/eax: byte = reg->data[0]
     8a/copy-byte *(eax+4) 0/r32/AL
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # if (prefix == 'x') push xmm register
     {
       3d/compare-eax-and 0x78/imm32/x
@@ -27918,7 +27918,7 @@ emit-push-register:  # out: (addr buffered-file), reg: (addr array byte)
       # var prefix/eax: byte = reg->data[3]
       8b/-> *(ebp+0xc) 0/r32/eax
       8a/copy-byte *(eax+7) 0/r32/AL
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       (write-byte-buffered *(ebp+8) %eax)
       (write-buffered *(ebp+8) "/x32\n")
       e9/jump $emit-push-register:end/disp32
@@ -27944,7 +27944,7 @@ emit-pop-register:  # out: (addr buffered-file), reg: (addr array byte)
     8b/-> *(ebp+0xc) 0/r32/eax
     # var prefix/eax: byte = reg->data[0]
     8a/copy-byte *(eax+4) 0/r32/AL
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
     # if (prefix == 'x') pop to xmm register
     {
       3d/compare-eax-and 0x78/imm32/x
@@ -27955,7 +27955,7 @@ emit-pop-register:  # out: (addr buffered-file), reg: (addr array byte)
       # var prefix/eax: byte = reg->data[3]
       8b/-> *(ebp+0xc) 0/r32/eax
       8a/copy-byte *(eax+7) 0/r32/AL
-      81 4/subop/and %eax 0xff/imm32
+      25/and-eax-with 0xff/imm32
       (write-byte-buffered *(ebp+8) %eax)
       (write-buffered *(ebp+8) "/x32\n")
       (emit-indent *(ebp+8) *Curr-block-depth)
@@ -30269,7 +30269,7 @@ power-of-2?:  # n: int, err: (addr buffered-file), ed: (addr exit-descriptor) ->
     # return (tmp2 == 0)
     3d/compare-eax-and 0/imm32
     0f 94/set-byte-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $power-of-2?:end:
     # . epilogue
     89/<- %esp 5/r32/ebp
@@ -36139,7 +36139,7 @@ subx-type-category-match?:  # a: (addr type-tree), b: (addr type-tree) -> result
     # return cata == catb
     39/compare %eax 1/r32/ecx
     0f 94/set-byte-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $subx-type-category-match?:end:
     # . restore registers
     59/pop-to-ecx
@@ -36182,7 +36182,7 @@ simple-mu-type?:  # a: (addr type-tree), n: type-id -> result/eax: boolean
     8b/-> *(ebp+8) 0/r32/eax
     39/compare *(eax+4) 1/r32/ecx  # Type-tree-value
     0f 94/set-byte-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $simple-mu-type?:end:
     # . restore registers
     59/pop-to-ecx
@@ -36206,7 +36206,7 @@ mu-addr-type?:  # a: (addr type-tree) -> result/eax: boolean
     # return (a->value == addr)
     81 7/subop/compare *(eax+4) 2/imm32/addr  # Type-tree-value
     0f 94/set-byte-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $mu-addr-type?:end:
     # . epilogue
     89/<- %esp 5/r32/ebp
@@ -36228,7 +36228,7 @@ mu-array-type?:  # a: (addr type-tree) -> result/eax: boolean
     # return (a->value == array)
     81 7/subop/compare *(eax+4) 3/imm32/array  # Type-tree-value
     0f 94/set-byte-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $mu-array-type?:end:
     # . epilogue
     89/<- %esp 5/r32/ebp
@@ -36290,7 +36290,7 @@ mu-stream-type?:  # a: (addr type-tree) -> result/eax: boolean
     # return (a->value == stream)
     81 7/subop/compare *(eax+4) 0xb/imm32/stream  # Type-tree-value
     0f 94/set-byte-if-= %al
-    81 4/subop/and %eax 0xff/imm32
+    25/and-eax-with 0xff/imm32
 $mu-stream-type?:end:
     # . epilogue
     89/<- %esp 5/r32/ebp
diff --git a/linux/sigils b/linux/sigils
index 88c96e10..64f78222 100755
Binary files a/linux/sigils and b/linux/sigils differ
diff --git a/linux/sigils.subx b/linux/sigils.subx
index 87d188a7..dd53efbe 100644
--- a/linux/sigils.subx
+++ b/linux/sigils.subx
@@ -1895,7 +1895,7 @@ test-next-word-or-expression:
     68/push  0xe/imm32
     # . . push slice->start - _test-input-stream
     8b/copy                         0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # copy *ecx to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -1908,7 +1908,7 @@ test-next-word-or-expression:
     68/push  0x10/imm32
     # . . push slice->end - _test-input-stream
     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           0/r32/eax   4/disp8         .                 # copy *(ecx+4) to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -1968,7 +1968,7 @@ test-next-word-or-expression-returns-whole-comment:
     68/push  0xe/imm32
     # . . push slice->start - _test-input-stream
     8b/copy                         0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # copy *ecx to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -1981,7 +1981,7 @@ test-next-word-or-expression-returns-whole-comment:
     68/push  0x11/imm32
     # . . push slice->end - _test-input-stream
     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           0/r32/eax   4/disp8         .                 # copy *(ecx+4) to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -2073,7 +2073,7 @@ test-next-word-or-expression-returns-string-literal:
     68/push  0xd/imm32
     # . . push slice->start - _test-input-stream
     8b/copy                         0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # copy *ecx to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -2086,7 +2086,7 @@ test-next-word-or-expression-returns-string-literal:
     68/push  0x18/imm32
     # . . push slice->end - _test-input-stream
     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           0/r32/eax   4/disp8         .                 # copy *(ecx+4) to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -2136,7 +2136,7 @@ test-next-word-or-expression-returns-string-with-escapes:
     68/push  0xd/imm32
     # . . push slice->start - _test-input-stream
     8b/copy                         0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # copy *ecx to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -2149,7 +2149,7 @@ test-next-word-or-expression-returns-string-with-escapes:
     68/push  0x15/imm32
     # . . push slice->end - _test-input-stream
     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           0/r32/eax   4/disp8         .                 # copy *(ecx+4) to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -2199,7 +2199,7 @@ test-next-word-or-expression-returns-whole-expression:
     68/push  0xd/imm32
     # . . push slice->start - _test-input-stream
     8b/copy                         0/mod/indirect  1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # copy *ecx to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -2212,7 +2212,7 @@ test-next-word-or-expression-returns-whole-expression:
     68/push  0x19/imm32
     # . . push slice->end - _test-input-stream
     8b/copy                         1/mod/*+disp8   1/rm32/ecx    .           .             .           0/r32/eax   4/disp8         .                 # copy *(ecx+4) to eax
-    81          5/subop/subtract    3/mod/direct    0/rm32/eax    .           .             .           .           .               _test-input-stream/imm32 # subtract from eax
+    2d/subtract-from-eax  _test-input-stream/imm32
     50/push-eax
     # . . call
     e8/call  check-ints-equal/disp32
@@ -2291,7 +2291,7 @@ $parse-effective-address:check-for-simple-register:
     # if (*local-slice->start == '(') goto compound expression
     8b/copy                         0/mod/indirect  6/rm32/esi    .           .             .           0/r32/eax   .               .                 # copy *esi to eax
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     3d/compare-eax-and  0x28/imm32/open-paren
     74/jump-if-=  $parse-effective-address:compound-expression/disp8
 $parse-effective-address:simple-register:
@@ -2357,7 +2357,7 @@ $parse-effective-address:compound-expression:
     89/copy                         0/mod/indirect  6/rm32/esi    .           .             .           0/r32/eax   .               .                 # copy eax to *esi
     # if (*local-slice->start == ')') goto end
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     3d/compare-eax-and  0x29/imm32/close-paren
     0f 84/jump-if-=  $parse-effective-address:end/disp32
     # if (*local-slice->start == '-') goto displacement
@@ -2434,7 +2434,7 @@ $parse-effective-address:index:
     89/copy                         0/mod/indirect  6/rm32/esi    .           .             .           0/r32/eax   .               .                 # copy eax to *esi
     # if (*local-slice->start == ')') goto end
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     3d/compare-eax-and  0x29/imm32/close-paren
     0f 84/jump-if-=  $parse-effective-address:end/disp32
 $parse-effective-address:check-for-scale:
@@ -2446,7 +2446,7 @@ $parse-effective-address:check-for-scale:
     # if (*local-slice->start != '<') goto error2
     8b/copy                         0/mod/indirect  6/rm32/esi    .           .             .           0/r32/eax   .               .                 # copy *esi to eax
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     3d/compare-eax-and  0x3c/imm32/less-than
     0f 85/jump-if-!=  $parse-effective-address:error2/disp32
     # ++local-slice->start to skip '<'
@@ -2486,7 +2486,7 @@ $parse-effective-address:scale:
     89/copy                         0/mod/indirect  6/rm32/esi    .           .             .           0/r32/eax   .               .                 # copy eax to *esi
     # if (*local-slice->start == ')') goto end
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     3d/compare-eax-and  0x29/imm32/close-paren
     74/jump-if-=  $parse-effective-address:end/disp8
 $parse-effective-address:check-for-displacement:
@@ -2520,7 +2520,7 @@ $parse-effective-address:displacement:
     89/copy                         0/mod/indirect  6/rm32/esi    .           .             .           0/r32/eax   .               .                 # copy eax to *esi
     # if (*local-slice->start != ')') goto error4
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     3d/compare-eax-and  0x29/imm32/close-paren
     0f 85/jump-if-!=  $parse-effective-address:error4/disp32
 $parse-effective-address:end:
@@ -3895,7 +3895,7 @@ disp32-mode?:  # in: (addr slice) -> reg/eax: boolean
     # if (*local-slice->start == '(') return false
     8b/copy                         0/mod/indirect  6/rm32/esi    .           .             .           0/r32/eax   .               .                 # copy *esi to eax
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     3d/compare-eax-and  0x28/imm32/open-paren
     74/jump-if-=  $disp32-mode?:false/disp8
 $disp32-mode?:check-for-register:
diff --git a/linux/survey_elf b/linux/survey_elf
index 87eba506..bd1c816c 100755
Binary files a/linux/survey_elf and b/linux/survey_elf differ
diff --git a/linux/survey_elf.subx b/linux/survey_elf.subx
index 211408cc..bfa76830 100644
--- a/linux/survey_elf.subx
+++ b/linux/survey_elf.subx
@@ -3119,7 +3119,7 @@ $far-jump-or-call?:check-second-word:
     8b/copy                         0/mod/indirect  2/rm32/edx    .           .             .           0/r32/eax   .               .                 # copy *edx to eax
     # . c/eax = *start
     8a/copy-byte                    0/mod/indirect  0/rm32/eax    .           .             .           0/r32/AL    .               .                 # copy byte at *eax to AL
-    81          4/subop/and         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xff/imm32        # bitwise and of eax
+    25/and-eax-with  0xff/imm32
     # . if (eax != '8') return
     3d/compare-eax-and  0x38/imm32/8
     75/jump-if-!=  $far-jump-or-call?:end/disp8
@@ -3257,7 +3257,7 @@ $emit-headers:loop:
     # . . discard args
     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
     # curr-segment += 20                        # size of a row
-    81          0/subop/add         3/mod/direct    0/rm32/eax    .           .             .           .           .               0x14/imm32        # add to eax
+    05/add-to-eax  0x14/imm32
     e9/jump  $emit-headers:loop/disp32
 $emit-headers:end:
     # . restore registers