diff --git a/docs/cton_domain.py b/docs/cton_domain.py
index 3dba386d90..a03acf1160 100644
--- a/docs/cton_domain.py
+++ b/docs/cton_domain.py
@@ -271,7 +271,10 @@ class InstDocumenter(sphinx.ext.autodoc.Documenter):
         return False
 
     def resolve_name(self, modname, parents, path, base):
-        return 'base.instructions', [base]
+        if path:
+            return path.rstrip('.'), [base]
+        else:
+            return 'base.instructions', [base]
 
     def format_signature(self):
         inst = self.object
diff --git a/docs/langref.rst b/docs/langref.rst
index 49593e3f09..dde7865486 100644
--- a/docs/langref.rst
+++ b/docs/langref.rst
@@ -775,15 +775,31 @@ the target ISA.
 .. autoinst:: isplit
 .. autoinst:: iconcat
 
-Base instruction group
-======================
+ISA-specific instructions
+=========================
+
+Target ISAs can define supplemental instructions that do not make sense to
+support generally.
+
+Intel
+-----
+
+Instructions that can only be used by the Intel target ISA.
+
+.. autoinst:: isa.intel.instructions.sdivmodx
+.. autoinst:: isa.intel.instructions.udivmodx
+
+Instruction groups
+==================
 
 All of the shared instructions are part of the :instgroup:`base` instruction
 group.
 
 .. autoinstgroup:: base.instructions.GROUP
 
-Target ISAs may define further instructions in their own instruction groups.
+Target ISAs may define further instructions in their own instruction groups:
+
+.. autoinstgroup:: isa.intel.instructions.GROUP
 
 Implementation limits
 =====================
diff --git a/filetests/isa/intel/binary32.cton b/filetests/isa/intel/binary32.cton
index 0eb136b5d6..67f37db11b 100644
--- a/filetests/isa/intel/binary32.cton
+++ b/filetests/isa/intel/binary32.cton
@@ -112,6 +112,19 @@ ebb0:
     ; asm: imull %ecx, %esi
     [-,%rsi]             v51 = imul v2, v1       ; bin: 0f af f1
 
+    ; asm: movl $1, %eax
+    [-,%rax]      v52 = iconst.i32 1                    ; bin: b8 00000001
+    ; asm: movl $2, %edx
+    [-,%rdx]      v53 = iconst.i32 2                    ; bin: ba 00000002
+    ; asm: idivl %ecx
+    [-,%rax,%rdx] v54, v55 = x86_sdivmodx v52, v53, v1  ; bin: f7 f9
+    ; asm: idivl %esi
+    [-,%rax,%rdx] v56, v57 = x86_sdivmodx v52, v53, v2  ; bin: f7 fe
+    ; asm: divl %ecx
+    [-,%rax,%rdx] v58, v59 = x86_udivmodx v52, v53, v1  ; bin: f7 f1
+    ; asm: divl %esi
+    [-,%rax,%rdx] v60, v61 = x86_udivmodx v52, v53, v2  ; bin: f7 f6
+
     ; Register copies.
 
     ; asm: movl %esi, %ecx
diff --git a/filetests/isa/intel/binary64.cton b/filetests/isa/intel/binary64.cton
index 5e3507d473..bed934d5ab 100644
--- a/filetests/isa/intel/binary64.cton
+++ b/filetests/isa/intel/binary64.cton
@@ -154,6 +154,21 @@ ebb0:
     ; asm: imulq %rcx, %r10
     [-,%r10]             v122 = imul v3, v1       ; bin: 4c 0f af d1
 
+    [-,%rax]      v130 = iconst.i64 1
+    [-,%rdx]      v131 = iconst.i64 2
+    ; asm: idivq %rcx
+    [-,%rax,%rdx] v132, v133 = x86_sdivmodx v130, v131, v1  ; bin: 48 f7 f9
+    ; asm: idivq %rsi
+    [-,%rax,%rdx] v134, v135 = x86_sdivmodx v130, v131, v2  ; bin: 48 f7 fe
+    ; asm: idivq %r10
+    [-,%rax,%rdx] v136, v137 = x86_sdivmodx v130, v131, v3  ; bin: 49 f7 fa
+    ; asm: divq %rcx
+    [-,%rax,%rdx] v138, v139 = x86_udivmodx v130, v131, v1  ; bin: 48 f7 f1
+    ; asm: divq %rsi
+    [-,%rax,%rdx] v140, v141 = x86_udivmodx v130, v131, v2  ; bin: 48 f7 f6
+    ; asm: divq %r10
+    [-,%rax,%rdx] v142, v143 = x86_udivmodx v130, v131, v3  ; bin: 49 f7 f2
+
     ; Bit-counting instructions.
 
     ; asm: popcntq %rsi, %rcx
@@ -331,6 +346,21 @@ ebb0:
     ; asm: imull %ecx, %r10d
     [-,%r10]             v122 = imul v3, v1       ; bin: 44 0f af d1
 
+    [-,%rax]      v130 = iconst.i32 1
+    [-,%rdx]      v131 = iconst.i32 2
+    ; asm: idivl %rcx
+    [-,%rax,%rdx] v132, v133 = x86_sdivmodx v130, v131, v1  ; bin: 40 f7 f9
+    ; asm: idivl %rsi
+    [-,%rax,%rdx] v134, v135 = x86_sdivmodx v130, v131, v2  ; bin: 40 f7 fe
+    ; asm: idivl %r10d
+    [-,%rax,%rdx] v136, v137 = x86_sdivmodx v130, v131, v3  ; bin: 41 f7 fa
+    ; asm: divl %rcx
+    [-,%rax,%rdx] v138, v139 = x86_udivmodx v130, v131, v1  ; bin: 40 f7 f1
+    ; asm: divl %rsi
+    [-,%rax,%rdx] v140, v141 = x86_udivmodx v130, v131, v2  ; bin: 40 f7 f6
+    ; asm: divl %r10d
+    [-,%rax,%rdx] v142, v143 = x86_udivmodx v130, v131, v3  ; bin: 41 f7 f2
+
     ; Bit-counting instructions.
 
     ; asm: popcntl %esi, %ecx
diff --git a/lib/cretonne/meta/isa/intel/defs.py b/lib/cretonne/meta/isa/intel/defs.py
index 50251b44af..5078bcec7e 100644
--- a/lib/cretonne/meta/isa/intel/defs.py
+++ b/lib/cretonne/meta/isa/intel/defs.py
@@ -6,8 +6,9 @@ Commonly used definitions.
 from __future__ import absolute_import
 from cdsl.isa import TargetISA, CPUMode
 import base.instructions
+from . import instructions as x86
 
-ISA = TargetISA('intel', [base.instructions.GROUP])
+ISA = TargetISA('intel', [base.instructions.GROUP, x86.GROUP])
 
 # CPU modes for 32-bit and 64-bit operation.
 I32 = CPUMode('I32', ISA)
diff --git a/lib/cretonne/meta/isa/intel/encodings.py b/lib/cretonne/meta/isa/intel/encodings.py
index f6f003bb1e..25421be999 100644
--- a/lib/cretonne/meta/isa/intel/encodings.py
+++ b/lib/cretonne/meta/isa/intel/encodings.py
@@ -8,6 +8,7 @@ from base.formats import UnaryImm
 from .defs import I32, I64
 from . import recipes as r
 from . import settings as cfg
+from . import instructions as x86
 
 for inst,           opc in [
         (base.iadd, 0x01),
@@ -28,6 +29,14 @@ I64.enc(base.imul.i64, *r.rrx.rex(0x0f, 0xaf, w=1))
 I64.enc(base.imul.i32, *r.rrx.rex(0x0f, 0xaf))
 I64.enc(base.imul.i32, *r.rrx(0x0f, 0xaf))
 
+for inst,              rrr in [
+        (x86.sdivmodx, 7),
+        (x86.udivmodx, 6)]:
+    I32.enc(inst.i32, *r.div(0xf7, rrr=rrr))
+    I64.enc(inst.i64, *r.div.rex(0xf7, rrr=rrr, w=1))
+    I64.enc(inst.i32, *r.div.rex(0xf7, rrr=rrr))
+    I64.enc(inst.i32, *r.div(0xf7, rrr=rrr))
+
 I32.enc(base.copy.i32, *r.umr(0x89))
 I64.enc(base.copy.i64, *r.umr.rex(0x89, w=1))
 I64.enc(base.copy.i32, *r.umr.rex(0x89))
diff --git a/lib/cretonne/meta/isa/intel/instructions.py b/lib/cretonne/meta/isa/intel/instructions.py
new file mode 100644
index 0000000000..a5c2bdafb0
--- /dev/null
+++ b/lib/cretonne/meta/isa/intel/instructions.py
@@ -0,0 +1,45 @@
+"""
+Supplementary instruction definitions for Intel.
+
+This module defines additional instructions that are useful only to the Intel
+target ISA.
+"""
+
+from cdsl.operands import Operand
+from cdsl.instructions import Instruction, InstructionGroup
+from base.instructions import iB
+
+
+GROUP = InstructionGroup("x86", "Intel-specific instruction set")
+
+nlo = Operand('nlo', iB, doc='Low part of numerator')
+nhi = Operand('nhi', iB, doc='High part of numerator')
+d = Operand('d', iB, doc='Denominator')
+q = Operand('q', iB, doc='Quotient')
+r = Operand('r', iB, doc='Remainder')
+
+udivmodx = Instruction(
+        'x86_udivmodx', r"""
+        Extended unsigned division.
+
+        Concatenate the bits in `nhi` and `nlo` to form the numerator.
+        Interpret the bits as an unsigned number and divide by the unsigned
+        denominator `d`. Trap when `d` is zero or if the quotient is larger
+        than the range of the output.
+
+        Return both quotient and remainder.
+        """,
+        ins=(nlo, nhi, d), outs=(q, r), can_trap=True)
+
+sdivmodx = Instruction(
+        'x86_sdivmodx', r"""
+        Extended signed division.
+
+        Concatenate the bits in `nhi` and `nlo` to form the numerator.
+        Interpret the bits as a signed number and divide by the signed
+        denominator `d`. Trap when `d` is zero or if the quotient is outside
+        the range of the output.
+
+        Return both quotient and remainder.
+        """,
+        ins=(nlo, nhi, d), outs=(q, r), can_trap=True)
diff --git a/lib/cretonne/meta/isa/intel/recipes.py b/lib/cretonne/meta/isa/intel/recipes.py
index e521b205b1..9c48a529d2 100644
--- a/lib/cretonne/meta/isa/intel/recipes.py
+++ b/lib/cretonne/meta/isa/intel/recipes.py
@@ -6,7 +6,7 @@ from cdsl.isa import EncRecipe
 from cdsl.predicates import IsSignedInt, IsEqual
 from base.formats import Unary, UnaryImm, Binary, BinaryImm, MultiAry
 from base.formats import Call, IndirectCall, Store, Load
-from base.formats import RegMove
+from base.formats import RegMove, Ternary
 from .registers import GPR, ABCD
 
 try:
@@ -239,6 +239,15 @@ rc = TailRecipe(
         modrm_r_bits(in_reg0, bits, sink);
         ''')
 
+# XX /n for division: inputs in %rax, %rdx, r. Outputs in %rax, %rdx.
+div = TailRecipe(
+        'div', Ternary, size=1,
+        ins=(GPR.rax, GPR.rdx, GPR), outs=(GPR.rax, GPR.rdx),
+        emit='''
+        PUT_OP(bits, rex1(in_reg2), sink);
+        modrm_r_bits(in_reg2, bits, sink);
+        ''')
+
 # XX /n ib with 8-bit immediate sign-extended.
 rib = TailRecipe(
         'rib', BinaryImm, size=2, ins=GPR, outs=0,