* config/tc-mips.c (MF_HILO_INSN): Define.

           (mips_7000_hilo_fix): Declare.
           (append_insn): Conditionally insert nops after an mfhi/mflo insn.
           (md_parse_option): Check for 7000_HILO_FIX options.
           (OPTION_M7000_HILO_FIX): Define.
           (OPTION_NO_M7000_HILO_FIX): Define.
           * doc/c-mips.texi (-mfix7000): Describe.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 1b944a968dfb049413d9d645a8cfe83cf7382182..eb6d0fb830958d43272491537e13c751e3ef2890 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2000-02-21  Catherine Moore  <clm@cygnus.com>
+
+       * config/tc-mips.c (MF_HILO_INSN): Define.
+       (mips_7000_hilo_fix): Declare.
+       (append_insn): Conditionally insert nops after an mfhi/mflo insn.
+       (md_parse_option): Check for 7000_HILO_FIX options.
+       (OPTION_M7000_HILO_FIX): Define.
+       (OPTION_NO_M7000_HILO_FIX): Define.
+       * doc/c-mips.texi (-mfix7000): Describe.
+
 2000-02-21  Alan Modra  <alan@spri.levels.unisa.edu.au>
 
        * listing.c (print_lines): Remove unused variable `end'.

diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index 723357a8706fbf2e7b59aeeeeb3e0f7852205937..f5b4d4e8f2f12d1a42f1c41821a0ded773affe82 100644 (file)
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -265,6 +265,10 @@ static int mips_32bitmode = 0;
 #define cop_interlocks (mips_cpu == 4300                            \
                        )
 
+/* Is this a mfhi or mflo instruction?  */
+#define MF_HILO_INSN(PINFO) \
+          ((PINFO & INSN_READ_HI) || (PINFO & INSN_READ_LO))
+
 /* MIPS PIC level.  */
 
 enum mips_pic_level
@@ -300,6 +304,10 @@ static int mips_trap;
 
 static int mips_any_noreorder;
 
+/* Non-zero if nops should be inserted when the register referenced in
+   an mfhi/mflo instruction is read in the next two instructions.  */
+static int mips_7000_hilo_fix;
+
 /* The size of the small data section.  */
 static int g_switch_value = 8;
 /* Whether the -G option was used.  */
@@ -1551,6 +1559,37 @@ append_insn (place, ip, address_expr, reloc_type, unmatched_hi)
              || (pinfo & INSN_READ_COND_CODE))
            ++nops;
        }
+
+      /* If we're fixing up mfhi/mflo for the r7000 and the
+        previous insn was an mfhi/mflo and the current insn
+        reads the register that the mfhi/mflo wrote to, then
+        insert two nops.  */
+
+      else if (mips_7000_hilo_fix
+              && MF_HILO_INSN (prev_pinfo)
+              && insn_uses_reg (ip, ((prev_insn.insn_opcode >> OP_SH_RD)
+                                       & OP_MASK_RD),
+                                    MIPS_GR_REG))
+
+       {
+         nops += 2;
+       }
+
+      /* If we're fixing up mfhi/mflo for the r7000 and the
+        2nd previous insn was an mfhi/mflo and the current insn
+        reads the register that the mfhi/mflo wrote to, then
+        insert one nop.  */
+
+      else if (mips_7000_hilo_fix
+              && MF_HILO_INSN (prev_prev_insn.insn_opcode)
+              && insn_uses_reg (ip, ((prev_prev_insn.insn_opcode >> OP_SH_RD)
+                                       & OP_MASK_RD),
+                                    MIPS_GR_REG))
+     
+       {
+         nops += 1;
+       }
+ 
       else if (prev_pinfo & INSN_READ_LO)
        {
          /* The previous instruction reads the LO register; if the
@@ -8802,6 +8841,11 @@ struct option md_longopts[] = {
 #define OPTION_MABI (OPTION_MD_BASE + 38)
   {"mabi", required_argument, NULL, OPTION_MABI},
 
+#define OPTION_M7000_HILO_FIX (OPTION_MD_BASE + 39)
+  {"mfix7000", no_argument, NULL, OPTION_M7000_HILO_FIX},
+#define OPTION_NO_M7000_HILO_FIX (OPTION_MD_BASE + 40)
+  {"no-fix-7000", no_argument, NULL, OPTION_NO_M7000_HILO_FIX},
+
 #define OPTION_CALL_SHARED (OPTION_MD_BASE + 7)
 #define OPTION_NON_SHARED (OPTION_MD_BASE + 8)
 #define OPTION_XGOT (OPTION_MD_BASE + 19)
@@ -9126,6 +9170,14 @@ md_parse_option (c, arg)
        mips_abi_string = arg;
       break;
 
+    case OPTION_M7000_HILO_FIX:
+      mips_7000_hilo_fix = true;
+      break;
+
+    case OPTION_NO_M7000_HILO_FIX:
+      mips_7000_hilo_fix = false;
+      break;
+
     default:
       return 0;
     }

diff --git a/gas/doc/c-mips.texi b/gas/doc/c-mips.texi
index 523dda3799f1730dcdde0d7a3aaf4ed9ed7aed59..fc2555a172ae205c72fdc204eaef75dd45f8c99e 100644 (file)
--- a/gas/doc/c-mips.texi
+++ b/gas/doc/c-mips.texi
@@ -73,6 +73,11 @@ Generate code for the MIPS 16 processor.  This is equivalent to putting
 @samp{.set mips16} at the start of the assembly file.  @samp{-no-mips16}
 turns off this option.
 
+@item -mfix7000
+@itemx -no-mfix7000
+Cause nops to be inserted if the read of the destination register
+of an mfhi or mflo instruction occurs in the following two instructions.
+
 @item -m4010
 @itemx -no-m4010
 Generate code for the LSI @sc{r4010} chip.  This tells the assembler to