[Qemu-devel] [RFC v3 12/24] riscv: tcg-target: Add the mov and movi instruction

[Alistair Francis]

Signed-off-by: Alistair Francis <address@hidden>
Signed-off-by: Michael Clark <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
 tcg/riscv/tcg-target.inc.c | 85 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/tcg/riscv/tcg-target.inc.c b/tcg/riscv/tcg-target.inc.c
index 05e85805d2..29275d6ac9 100644
--- a/tcg/riscv/tcg-target.inc.c
+++ b/tcg/riscv/tcg-target.inc.c
@@ -497,3 +497,88 @@ static void patch_reloc(tcg_insn_unit *code_ptr, int type,
         tcg_abort();
     }
 }
+
+/*
+ * TCG intrinsics
+ */
+
+static void tcg_out_mov(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
+{
+    if (ret == arg) {
+        return;
+    }
+    switch (type) {
+    case TCG_TYPE_I32:
+    case TCG_TYPE_I64:
+        tcg_out_opc_imm(s, OPC_ADDI, ret, arg, 0);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+}
+
+static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg rd,
+                         tcg_target_long val)
+{
+    tcg_target_long lo, hi, tmp;
+    int shift;
+
+    if (TCG_TARGET_REG_BITS == 64 && type == TCG_TYPE_I32) {
+        val = (int32_t)val;
+    }
+
+    lo = sextreg(val, 0, 12);
+    if (val == lo) {
+        tcg_out_opc_imm(s, OPC_ADDI, rd, TCG_REG_ZERO, lo);
+        return;
+    }
+
+    hi = val - lo;
+    if (TCG_TARGET_REG_BITS == 32 || val == (int32_t)val) {
+        tcg_out_opc_upper(s, OPC_LUI, rd, hi);
+        if (lo != 0) {
+            tcg_out_opc_imm(s, OPC_ADDIW, rd, rd, lo);
+        }
+        return;
+    }
+
+    /* We can only be here if TCG_TARGET_REG_BITS != 32 */
+    tmp = tcg_pcrel_diff(s, (void *)val);
+    if (tmp == (int32_t)tmp) {
+        tcg_out_opc_upper(s, OPC_AUIPC, rd, 0);
+        tcg_out_opc_imm(s, OPC_ADDI, rd, rd, 0);
+        reloc_call(s->code_ptr - 2, (tcg_insn_unit *)val);
+        return;
+    }
+
+    /* Look for a single 20-bit section.  */
+    shift = ctz64(val);
+    tmp = val >> shift;
+    if (tmp == sextreg(tmp, 0, 20)) {
+        tcg_out_opc_upper(s, OPC_LUI, rd, tmp << 12);
+        if (shift > 12) {
+            tcg_out_opc_imm(s, OPC_SLLI, rd, rd, shift - 12);
+        } else {
+            tcg_out_opc_imm(s, OPC_SRAI, rd, rd, 12 - shift);
+        }
+        return;
+    }
+
+    /* Look for a few high zero bits, with lots of bits set in the middle.  */
+    shift = clz64(val);
+    tmp = val << shift;
+    if (tmp == sextreg(tmp, 12, 20) << 12) {
+        tcg_out_opc_upper(s, OPC_LUI, rd, tmp);
+        tcg_out_opc_imm(s, OPC_SRLI, rd, rd, shift);
+        return;
+    } else if (tmp == sextreg(tmp, 0, 12)) {
+        tcg_out_opc_imm(s, OPC_ADDI, rd, TCG_REG_ZERO, tmp);
+        tcg_out_opc_imm(s, OPC_SRLI, rd, rd, shift);
+        return;
+    }
+
+    /* Drop into the constant pool.  */
+    new_pool_label(s, val, R_RISCV_CALL, s->code_ptr, 0);
+    tcg_out_opc_upper(s, OPC_AUIPC, rd, 0);
+    tcg_out_opc_imm(s, OPC_LD, rd, rd, 0);
+}
-- 
2.19.1