[Qemu-devel] [PATCH v3 18/29] tcg-aarch64: Support div, rem

[Richard Henderson]

For remainder, generic code will produce mul+sub,
whereas we can implement with msub.

Signed-off-by: Richard Henderson <address@hidden>
---
 tcg/aarch64/tcg-target.c | 50 +++++++++++++++++++++++++++++++++++++++---------
 tcg/aarch64/tcg-target.h |  8 ++++----
 2 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
index 5ab0596..09ccd67 100644
--- a/tcg/aarch64/tcg-target.c
+++ b/tcg/aarch64/tcg-target.c
@@ -297,6 +297,12 @@ typedef enum {
     INSN_RORV  = 0x1ac02c00,
     INSN_SMULH = 0x9b407c00,
     INSN_UMULH = 0x9bc07c00,
+    INSN_UDIV  = 0x1ac00800,
+    INSN_SDIV  = 0x1ac00c00,
+
+    /* Data-processing (3 source) instructions */
+    INSN_MADD  = 0x1b000000,
+    INSN_MSUB  = 0x1b008000,
 
     /* Bitfield instructions */
     INSN_BFM   = 0x33000000,
@@ -398,6 +404,12 @@ static inline void tcg_fmt_Rdnm(TCGContext *s, AArch64Insn 
insn, bool ext,
     tcg_out32(s, insn | ext << 31 | rm << 16 | rn << 5 | rd);
 }
 
+static inline void tcg_fmt_Rdnma(TCGContext *s, AArch64Insn insn, bool ext,
+                                 TCGReg rd, TCGReg rn, TCGReg rm, TCGReg ra)
+{
+    tcg_out32(s, insn | ext << 31 | rm << 16 | ra << 10 | rn << 5 | rd);
+}
+
 static inline void tcg_fmt_Rdnm_shift(TCGContext *s, AArch64Insn insn,
                                       bool ext, TCGReg rd, TCGReg rn,
                                       TCGReg rm, int shift_imm)
@@ -604,14 +616,6 @@ static inline void tcg_out_st(TCGContext *s, TCGType type, 
TCGReg arg,
                  arg, arg1, arg2);
 }
 
-static inline void tcg_out_mul(TCGContext *s, bool ext,
-                               TCGReg rd, TCGReg rn, TCGReg rm)
-{
-    /* Using MADD 0x1b000000 with Ra = wzr alias MUL 0x1b007c00 */
-    unsigned int base = ext ? 0x9b007c00 : 0x1b007c00;
-    tcg_out32(s, base | rm << 16 | rn << 5 | rd);
-}
-
 static inline void tcg_out_bfm(TCGContext *s, bool ext, TCGReg rd, TCGReg rn,
                                unsigned int a, unsigned int b)
 {
@@ -1404,7 +1408,27 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
 
     case INDEX_op_mul_i64:
     case INDEX_op_mul_i32:
-        tcg_out_mul(s, ext, a0, a1, a2);
+        tcg_fmt_Rdnma(s, INSN_MADD, ext, a0, a1, a2, TCG_REG_XZR);
+        break;
+
+    case INDEX_op_div_i64:
+    case INDEX_op_div_i32:
+        tcg_fmt_Rdnm(s, INSN_SDIV, ext, a0, a1, a2);
+        break;
+    case INDEX_op_divu_i64:
+    case INDEX_op_divu_i32:
+        tcg_fmt_Rdnm(s, INSN_UDIV, ext, a0, a1, a2);
+        break;
+
+    case INDEX_op_rem_i64:
+    case INDEX_op_rem_i32:
+        tcg_fmt_Rdnm(s, INSN_SDIV, ext, TCG_REG_TMP, a1, a2);
+        tcg_fmt_Rdnma(s, INSN_MSUB, ext, a0, TCG_REG_TMP, a2, a1);
+        break;
+    case INDEX_op_remu_i64:
+    case INDEX_op_remu_i32:
+        tcg_fmt_Rdnm(s, INSN_UDIV, ext, TCG_REG_TMP, a1, a2);
+        tcg_fmt_Rdnma(s, INSN_MSUB, ext, a0, TCG_REG_TMP, a2, a1);
         break;
 
     case INDEX_op_shl_i64:
@@ -1637,6 +1661,14 @@ static const TCGTargetOpDef aarch64_op_defs[] = {
     { INDEX_op_sub_i64, { "r", "rZ", "rA" } },
     { INDEX_op_mul_i32, { "r", "r", "r" } },
     { INDEX_op_mul_i64, { "r", "r", "r" } },
+    { INDEX_op_div_i32, { "r", "r", "r" } },
+    { INDEX_op_div_i64, { "r", "r", "r" } },
+    { INDEX_op_divu_i32, { "r", "r", "r" } },
+    { INDEX_op_divu_i64, { "r", "r", "r" } },
+    { INDEX_op_rem_i32, { "r", "r", "r" } },
+    { INDEX_op_rem_i64, { "r", "r", "r" } },
+    { INDEX_op_remu_i32, { "r", "r", "r" } },
+    { INDEX_op_remu_i64, { "r", "r", "r" } },
     { INDEX_op_and_i32, { "r", "r", "rwL" } },
     { INDEX_op_and_i64, { "r", "r", "rL" } },
     { INDEX_op_or_i32, { "r", "r", "rwL" } },
diff --git a/tcg/aarch64/tcg-target.h b/tcg/aarch64/tcg-target.h
index 8fd6771..bf72e62 100644
--- a/tcg/aarch64/tcg-target.h
+++ b/tcg/aarch64/tcg-target.h
@@ -39,8 +39,8 @@ typedef enum {
 #define TCG_TARGET_CALL_STACK_OFFSET    0
 
 /* optional instructions */
-#define TCG_TARGET_HAS_div_i32          0
-#define TCG_TARGET_HAS_rem_i32          0
+#define TCG_TARGET_HAS_div_i32          1
+#define TCG_TARGET_HAS_rem_i32          1
 #define TCG_TARGET_HAS_ext8s_i32        1
 #define TCG_TARGET_HAS_ext16s_i32       1
 #define TCG_TARGET_HAS_ext8u_i32        1
@@ -64,8 +64,8 @@ typedef enum {
 #define TCG_TARGET_HAS_muluh_i32        0
 #define TCG_TARGET_HAS_mulsh_i32        0
 
-#define TCG_TARGET_HAS_div_i64          0
-#define TCG_TARGET_HAS_rem_i64          0
+#define TCG_TARGET_HAS_div_i64          1
+#define TCG_TARGET_HAS_rem_i64          1
 #define TCG_TARGET_HAS_ext8s_i64        1
 #define TCG_TARGET_HAS_ext16s_i64       1
 #define TCG_TARGET_HAS_ext32s_i64       1
-- 
1.8.3.1