[05/28] target/riscv: Convert RVXI fence insns to decodetree

Commit Message

Bastian Koppelmann Oct. 12, 2018, 5:30 p.m. UTC

Signed-off-by: Bastian Koppelmann <[e-mail]>
Signed-off-by: Peer Adelt <[e-mail]>
---
 target/riscv/insn32.decode              |  8 ++++++++
 target/riscv/insn_trans/trans_rvi.inc.c | 20 ++++++++++++++++++++
 target/riscv/translate.c                | 14 --------------
 3 files changed, 28 insertions(+), 14 deletions(-)

Comments

Richard Henderson Oct. 12, 2018, 7:17 p.m. UTC | #1

On 10/12/18 10:30 AM, Bastian Koppelmann wrote:
> +%pred   24:4
> +%succ   20:4
...
> +@noargs  ................................
...
> +@fence   .... .... .... .....  ... ..... ....... %pred %succ
...
> +fence    0000 .... ....   00000 000 00000 0001111 @fence
> +fence_i  000000000000     00000 001 00000 0001111 @noargs

@noargs is useless, even as documentation, since by its omission there are no
arguments.

Also, "the unused fields in the FENCE instruction, imm[11:8], rs1, and rd, are
reserved for finer-grain fences in future extensions. For forward
compatibility, base implementations shall ignore these fields, and standard
software shall zero these fields."

Therefore "-" not "0" in the relevant portions.  And for clarity I would simply
fold it all together as

fence	---- pred:4 succ:4 ----- 000 ----- 0001111
fence_i	---- ----   ----   ----- 001 ----- 0001111

Or just use "@i", which is the underlying format and ignore the rs1 and rd
fields in the trans_ expanders, and pull pred+succ out of imm there.


r~

Patch

diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
index cb7622e223..695577b19b 100644
--- a/target/riscv/insn32.decode
+++ b/target/riscv/insn32.decode
@@ -24,6 +24,9 @@ 
 %sh6    20:6
 %sh5    20:5
 
+%pred   24:4
+%succ   20:4
+
 # immediates:
 %imm_i    20:s12
 %imm_s    25:s7 7:5
@@ -36,6 +39,8 @@ 
 &shift     shamt rs1 rd
 
 # Formats 32:
+@noargs  ................................
+
 @r       .......   ..... ..... ... ..... .......                   %rs2 %rs1 %rd
 @i       ............    ..... ... ..... .......         imm=%imm_i     %rs1 %rd
 @b       .......   ..... ..... ... ..... ....... &branch imm=%imm_b %rs2 %rs1
@@ -45,6 +50,7 @@ 
 
 @sh6     ......  ...... .....  ... ..... ....... &shift  shamt=%sh6      %rs1 %rd
 @sh5     .......  ..... .....  ... ..... ....... &shift  shamt=%sh5      %rs1 %rd
+@fence   .... .... .... .....  ... ..... ....... %pred %succ
 
 # *** RV32I Base Instruction Set ***
 lui      ....................       ..... 0110111 @u
@@ -84,6 +90,8 @@  srl      0000000 .....    ..... 101 ..... 0110011 @r
 sra      0100000 .....    ..... 101 ..... 0110011 @r
 or       0000000 .....    ..... 110 ..... 0110011 @r
 and      0000000 .....    ..... 111 ..... 0110011 @r
+fence    0000 .... ....   00000 000 00000 0001111 @fence
+fence_i  000000000000     00000 001 00000 0001111 @noargs
 
 # *** RV64I Base Instruction Set (in addition to RV32I) ***
 lwu      ............   ..... 110 ..... 0000011 @i
diff --git a/target/riscv/insn_trans/trans_rvi.inc.c b/target/riscv/insn_trans/trans_rvi.inc.c
index 2b017cf4a4..f532ca48e8 100644
--- a/target/riscv/insn_trans/trans_rvi.inc.c
+++ b/target/riscv/insn_trans/trans_rvi.inc.c
@@ -377,3 +377,23 @@  static bool trans_sraw(DisasContext *ctx, arg_sraw *a, uint32_t insn)
     gen_arith(ctx, OPC_RISC_SRAW, a->rd, a->rs1, a->rs2);
     return true;
 }
+
+static bool trans_fence(DisasContext *ctx, arg_fence *a, uint32_t insn)
+{
+#ifndef CONFIG_USER_ONLY
+    /* FENCE is a full memory barrier. */
+    tcg_gen_mb(TCG_MO_ALL | TCG_BAR_SC);
+#endif
+    return true;
+}
+static bool trans_fence_i(DisasContext *ctx, arg_fence_i *a, uint32_t insn)
+{
+#ifndef CONFIG_USER_ONLY
+    /* FENCE_I is a no-op in QEMU,
+     * however we need to end the translation block */
+    tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn);
+    tcg_gen_exit_tb(NULL, 0);
+    ctx->base.is_jmp = DISAS_NORETURN;
+#endif
+    return true;
+}
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 96169c4935..08c3b73c1a 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1739,20 +1739,6 @@  static void decode_RV32_64G(CPURISCVState *env, DisasContext *ctx)
         gen_fp_arith(ctx, MASK_OP_FP_ARITH(ctx->opcode), rd, rs1, rs2,
                      GET_RM(ctx->opcode));
         break;
-    case OPC_RISC_FENCE:
-#ifndef CONFIG_USER_ONLY
-        if (ctx->opcode & 0x1000) {
-            /* FENCE_I is a no-op in QEMU,
-             * however we need to end the translation block */
-            tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn);
-            tcg_gen_exit_tb(NULL, 0);
-            ctx->base.is_jmp = DISAS_NORETURN;
-        } else {
-            /* FENCE is a full memory barrier. */
-            tcg_gen_mb(TCG_MO_ALL | TCG_BAR_SC);
-        }
-#endif
-        break;
     case OPC_RISC_SYSTEM:
         gen_system(env, ctx, MASK_OP_SYSTEM(ctx->opcode), rd, rs1,
                    (ctx->opcode & 0xFFF00000) >> 20);