diff --git a/gas/ChangeLog b/gas/ChangeLog
index 4040f2e63e..5b4d747bfc 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,9 @@
+2004-01-24  Chris Demetriou  <cgd@broadcom.com>
+
+	* config/tc-mips.c (hilo_interlocks): Change definition
+	so that MIPS32, MIPS64 and later ISAs are included, along with
+	the already-included machines.  Update comments.
+
 2004-01-23  Daniel Jacobowitz  <drow@mvista.com>
 
 	* config/tc-arm.c (tc_gen_reloc): Improve error message for
diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index 201eb61694..42efce32ee 100644
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -325,15 +325,30 @@ static int mips_32bitmode = 0;
 /* True if CPU has a ror instruction.  */
 #define CPU_HAS_ROR(CPU)	CPU_HAS_DROR (CPU)
 
-/* Whether the processor uses hardware interlocks to protect
-   reads from the HI and LO registers, and thus does not
-   require nops to be inserted.  */
+/* True if mflo and mfhi can be immediately followed by instructions
+   which write to the HI and LO registers.
 
-#define hilo_interlocks (mips_opts.arch == CPU_R4010                       \
-                         || mips_opts.arch == CPU_VR5500                   \
-                         || mips_opts.arch == CPU_RM7000                   \
-                         || mips_opts.arch == CPU_SB1                      \
-                         )
+   According to MIPS specifications, MIPS ISAs I, II, and III need
+   (at least) two instructions between the reads of HI/LO and
+   instructions which write them, and later ISAs do not.  Contradicting
+   the MIPS specifications, some MIPS IV processor user manuals (e.g.
+   the UM for the NEC Vr5000) document needing the instructions between
+   HI/LO reads and writes, as well.  Therefore, we declare only MIPS32,
+   MIPS64 and later ISAs to have the interlocks, plus any specific
+   earlier-ISA CPUs for which CPU documentation declares that the
+   instructions are really interlocked.  */
+#define hilo_interlocks \
+  (mips_opts.isa == ISA_MIPS32                        \
+   || mips_opts.isa == ISA_MIPS32R2                   \
+   || mips_opts.isa == ISA_MIPS64                     \
+   || mips_opts.isa == ISA_MIPS64R2                   \
+   || mips_opts.arch == CPU_R4010                     \
+   || mips_opts.arch == CPU_R10000                    \
+   || mips_opts.arch == CPU_R12000                    \
+   || mips_opts.arch == CPU_RM7000                    \
+   || mips_opts.arch == CPU_SB1                       \
+   || mips_opts.arch == CPU_VR5500                    \
+   )
 
 /* Whether the processor uses hardware interlocks to protect reads
    from the GPRs after they are loaded from memory, and thus does not