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[Qemu-devel] [PATCH 3/3] tcg-mips: Implement movcond.


From: Richard Henderson
Subject: [Qemu-devel] [PATCH 3/3] tcg-mips: Implement movcond.
Date: Sat Dec 19 14:32:13 PST 2009

---
 tcg/mips/tcg-target.c |  119 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 117 insertions(+), 2 deletions(-)

diff --git a/tcg/mips/tcg-target.c b/tcg/mips/tcg-target.c
index 2a2913d..123a7af 100644
--- a/tcg/mips/tcg-target.c
+++ b/tcg/mips/tcg-target.c
@@ -297,6 +297,8 @@ enum {
     OPC_SRAV     = OPC_SPECIAL | 0x07,
     OPC_JR       = OPC_SPECIAL | 0x08,
     OPC_JALR     = OPC_SPECIAL | 0x09,
+    OPC_MOVZ     = OPC_SPECIAL | 0x0A,
+    OPC_MOVN     = OPC_SPECIAL | 0x0B,
     OPC_MFHI     = OPC_SPECIAL | 0x10,
     OPC_MFLO     = OPC_SPECIAL | 0x12,
     OPC_MULT     = OPC_SPECIAL | 0x18,
@@ -464,8 +466,8 @@ static inline void tcg_out_addi(TCGContext *s, int reg, 
tcg_target_long val)
     }
 }
 
-static void tcg_out_brcond(TCGContext *s, int cond, int arg1,
-                           int arg2, int label_index)
+static void tcg_out_brcond_nodelay(TCGContext *s, int cond, int arg1,
+                                   int arg2, int label_index)
 {
     TCGLabel *l = &s->labels[label_index];
 
@@ -517,6 +519,12 @@ static void tcg_out_brcond(TCGContext *s, int cond, int 
arg1,
     } else {
         tcg_out_reloc(s, s->code_ptr - 4, R_MIPS_PC16, label_index, 0);
     }
+}
+
+static void tcg_out_brcond(TCGContext *s, int cond, int arg1,
+                           int arg2, int label_index)
+{
+    tcg_out_brcond_nodelay(s, cond, arg1, arg2, label_index);
     tcg_out_nop(s);
 }
 
@@ -749,6 +757,108 @@ static void tcg_out_setcond2(TCGContext *s, int cond, int 
dest,
     }
 }
 
+static inline int have_movz(void)
+{
+    /* ??? It's unclear what we want to do with different mips isa's.
+       We appear to already be assuming HILO interlocks on the MUL/DIV
+       instructions, which (according to gcc) implies MIPS{32,64} plus
+       the r5500.  All of these also have MUL3, which would elide the
+       use of the LO register for simple multiply.  MIPS{4,32,64} have
+       the conditional moves, but the r5500 doesn't.  */
+#if defined(__mips) && __mips >= 32
+    /* Use MOVZ on MIPS{32,64}.  */
+    return 1;
+#else
+    /* Mips has no architected cpuid.  We could probably look at
+       /proc/cpuinfo or similar to figure out what's running.  */
+    return 0;
+#endif
+}
+
+static void tcg_out_movcond(TCGContext *s, int cond, int dest,
+                            int c1, int c2, int c2const, int vt, int vf)
+{
+    int condr;
+
+    if (vt == vf) {
+        tcg_out_mov(s, dest, vt);
+        return;
+    }
+
+    if (dest == vt) {
+        vt = vf, vf = dest;
+        cond = tcg_invert_cond(cond);
+    }
+
+    condr = TCG_COND_NE;
+    switch (cond) {
+    case TCG_COND_EQ:
+        condr = TCG_COND_EQ;
+        /* FALLTHRU */
+    case TCG_COND_NE:
+        if (c2 != 0) {
+            if (c2const)
+                tcg_out_opc_imm(s, OPC_XORI, TCG_REG_T0, c1, c2);
+            else
+                tcg_out_opc_reg(s, OPC_XOR, TCG_REG_T0, c1, c2);
+            c1 = TCG_REG_T0;
+        }
+        break;
+
+    case TCG_COND_LE:
+    case TCG_COND_LEU:
+        if (c2const && c2 < 32767) {
+            c2++;
+            cond = (cond == TCG_COND_LE ? TCG_COND_LT : TCG_COND_LTU);
+            goto do_setcond;
+        }
+        /* FALLTHRU */
+
+    case TCG_COND_GE:
+    case TCG_COND_GEU:
+        cond = tcg_invert_cond(cond);
+        condr = TCG_COND_EQ;
+        /* FALLTHRU */
+
+    case TCG_COND_LT:
+    case TCG_COND_LTU:
+    case TCG_COND_GT:
+    case TCG_COND_GTU:
+    do_setcond:
+        tcg_out_setcond(s, cond, TCG_REG_T0, c1, c2, c2const);
+        c1 = TCG_REG_T0;
+        break;
+
+    default:
+        tcg_abort();
+    }
+
+    if (have_movz()) {
+        if (dest != vf) {
+            if (dest == c1) {
+                tcg_out_mov(s, TCG_REG_AT, c1);
+                c1 = TCG_REG_AT;
+            }
+            tcg_out_mov(s, dest, vf);
+        }
+        tcg_out_opc_reg(s, (condr == TCG_COND_NE ? OPC_MOVN : OPC_MOVZ),
+                        dest, vt, c1);
+    } else {
+        int label_over = gen_new_label();
+
+        tcg_out_brcond_nodelay(s, tcg_invert_cond(condr),
+                               c1, TCG_REG_ZERO, label_over);
+        if (dest != vf) {
+            tcg_out_mov(s, dest, vf);
+        } else {
+            tcg_out_nop(s);
+        }
+
+        tcg_out_mov(s, dest, vt);
+        tcg_out_label(s, label_over, (tcg_target_long)s->code_ptr);
+    }
+}
+
 #if defined(CONFIG_SOFTMMU)
 
 #include "../../softmmu_defs.h"
@@ -1328,6 +1438,10 @@ static inline void tcg_out_op(TCGContext *s, int opc,
         tcg_out_setcond2(s, args[5], args[0], args[1], args[2],
                          args[3], args[4], const_args[3], const_args[4]);
         break;
+    case INDEX_OP_movcond_i32:
+        tcg_out_movcond(s, args[5], args[0], args[1], args[2], const_args[2],
+                        args[3], args[4]);
+        break;
 
     case INDEX_op_qemu_ld8u:
         tcg_out_qemu_ld(s, args, 0);
@@ -1409,6 +1523,7 @@ static const TCGTargetOpDef mips_op_defs[] = {
 
     { INDEX_op_setcond_i32, { "r", "r", "rJ" } },
     { INDEX_op_setcond2_i32, { "r", "r", "r", "rJ", "rJ" } },
+    { INDEX_op_movcond_i32, { "r", "r", "rJ", "rZ", "rZ" } },
 
 #if TARGET_LONG_BITS == 32
     { INDEX_op_qemu_ld8u, { "L", "lZ" } },
-- 
1.6.5.2





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