tcg-arm: Implement division instructions

An armv7 extension implements division, present on Cortex A15.
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

disas/arm.c

@@ -819,6 +819,10 @@ static const struct opcode32 arm_opcodes[] =
   {ARM_EXT_V3M, 0x00800090, 0x0fa000f0, "%22?sumull%20's%c\t%12-15r, %16-19r, %0-3r, %8-11r"},
   {ARM_EXT_V3M, 0x00a00090, 0x0fa000f0, "%22?sumlal%20's%c\t%12-15r, %16-19r, %0-3r, %8-11r"},
 
+  /* IDIV instructions.  */
+  {ARM_EXT_DIV, 0x0710f010, 0x0ff0f0f0, "sdiv%c\t%16-19r, %0-3r, %8-11r"},
+  {ARM_EXT_DIV, 0x0730f010, 0x0ff0f0f0, "udiv%c\t%16-19r, %0-3r, %8-11r"},
+
   /* V7 instructions.  */
   {ARM_EXT_V7, 0xf450f000, 0xfd70f000, "pli\t%P"},
   {ARM_EXT_V7, 0x0320f0f0, 0x0ffffff0, "dbg%c\t#%0-3d"},

tcg/arm/tcg-target.c

@@ -597,6 +597,16 @@ static inline void tcg_out_smull32(TCGContext *s,
     }
 }
 
+static inline void tcg_out_sdiv(TCGContext *s, int cond, int rd, int rn, int rm)
+{
+    tcg_out32(s, 0x0710f010 | (cond << 28) | (rd << 16) | rn | (rm << 8));
+}
+
+static inline void tcg_out_udiv(TCGContext *s, int cond, int rd, int rn, int rm)
+{
+    tcg_out32(s, 0x0730f010 | (cond << 28) | (rd << 16) | rn | (rm << 8));
+}
+
 static inline void tcg_out_ext8s(TCGContext *s, int cond,
                                  int rd, int rn)
 {
@@ -1868,6 +1878,25 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
                         args[3], args[4], const_args[2]);
         break;
 
+    case INDEX_op_div_i32:
+        tcg_out_sdiv(s, COND_AL, args[0], args[1], args[2]);
+        break;
+    case INDEX_op_divu_i32:
+        tcg_out_udiv(s, COND_AL, args[0], args[1], args[2]);
+        break;
+    case INDEX_op_rem_i32:
+        tcg_out_sdiv(s, COND_AL, TCG_REG_R8, args[1], args[2]);
+        tcg_out_mul32(s, COND_AL, TCG_REG_R8, TCG_REG_R8, args[2]);
+        tcg_out_dat_reg(s, COND_AL, ARITH_SUB, args[0], args[1], TCG_REG_R8,
+                        SHIFT_IMM_LSL(0));
+        break;
+    case INDEX_op_remu_i32:
+        tcg_out_udiv(s, COND_AL, TCG_REG_R8, args[1], args[2]);
+        tcg_out_mul32(s, COND_AL, TCG_REG_R8, TCG_REG_R8, args[2]);
+        tcg_out_dat_reg(s, COND_AL, ARITH_SUB, args[0], args[1], TCG_REG_R8,
+                        SHIFT_IMM_LSL(0));
+        break;
+
     default:
         tcg_abort();
     }
@@ -1954,6 +1983,13 @@ static const TCGTargetOpDef arm_op_defs[] = {
 
     { INDEX_op_deposit_i32, { "r", "0", "rZ" } },
 
+#if TCG_TARGET_HAS_div_i32
+    { INDEX_op_div_i32, { "r", "r", "r" } },
+    { INDEX_op_rem_i32, { "r", "r", "r" } },
+    { INDEX_op_divu_i32, { "r", "r", "r" } },
+    { INDEX_op_remu_i32, { "r", "r", "r" } },
+#endif
+
     { -1 },
 };
 

tcg/arm/tcg-target.h

@@ -56,7 +56,6 @@ typedef enum {
 #define TCG_TARGET_CALL_STACK_OFFSET	0
 
 /* optional instructions */
-#define TCG_TARGET_HAS_div_i32          0
 #define TCG_TARGET_HAS_ext8s_i32        1
 #define TCG_TARGET_HAS_ext16s_i32       1
 #define TCG_TARGET_HAS_ext8u_i32        0 /* and r0, r1, #0xff */
@@ -75,6 +74,12 @@ typedef enum {
 #define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_muls2_i32        1
 
+#ifdef __ARM_ARCH_EXT_IDIV__
+#define TCG_TARGET_HAS_div_i32          1
+#else
+#define TCG_TARGET_HAS_div_i32          0
+#endif
+
 extern bool tcg_target_deposit_valid(int ofs, int len);
 #define TCG_TARGET_deposit_i32_valid  tcg_target_deposit_valid