diff --git a/sim/riscv/sim-main.c b/sim/riscv/sim-main.c
index e715ca2501e..66e0610c246 100644
--- a/sim/riscv/sim-main.c
+++ b/sim/riscv/sim-main.c
@@ -1036,6 +1036,77 @@ float32_math (SIM_CPU *cpu, int rd, int rs1, int rs2,
     }
 }
 
+/* Round and return the double value.  This function is used before we
+   perform any operation on the input double value.  */
+static double
+round_double_input (double value, int rm)
+{
+  double result = value;
+  if (rm == RNE)
+    {
+      double fractional_part = value - trunc (value);
+      /* Check if the number is halfway between two values.  */
+      if (fractional_part == 0.5 || fractional_part == -0.5)
+	{
+	  result = floor (value);
+	  if (fmod (result, 2.0) != 0)
+	    result += (value > 0) ? 1.0 : -1.0;
+	}
+      else
+	result = round (value);
+    }
+  else if (rm == RTZ)
+    result = trunc (value);
+  else if (rm == RDN)
+    result = floor (value);
+  else if (rm == RUP)
+    result = ceil (value);
+  else
+    {
+      /* No direct match for RMM.  Simulate it.  */
+      double fracPart = value - (int64_t) value;
+      if (fracPart > 0.5 || fracPart < -0.5)
+	result = round (value);
+      else if (fracPart == 0.5)
+	result = ceil (value);
+      else if (fracPart == -0.5)
+	result = floor (value);
+      else
+	result = value;
+    }
+  return result;
+}
+
+/* Round and return the double value.  This function is used after we
+   perform the operation to get the result rounded.  */
+static double
+round_double_output (double value, int rm)
+{
+  double result;
+  if (rm == RNE)
+    result = value;
+  else if (rm == RTZ)
+    result = trunc (value);
+  else if (rm == RDN)
+    result = floor (value);
+  else if (rm == RUP)
+    result = ceil (value);
+  else
+    {
+      /* No direct match for RMM.  Simulate it.  */
+      double fracPart = value - (int64_t) value;
+      if (fracPart > 0.5 || fracPart < -0.5)
+	result = round (value);
+      else if (fracPart == 0.5)
+	result = ceil (value);
+      else if (fracPart == -0.5)
+	result = floor (value);
+      else
+	result = value;
+    }
+  return result;
+}
+
 /* Round and return the float value.  This function is used before we
    perform any operation on the input float value.  */
 static float
@@ -1107,6 +1178,183 @@ round_float_output (float value, int rm)
   return result;
 }
 
+/* Convert the double precision floating point value into integer.  */
+static void
+convert_double_to_int (SIM_CPU *cpu, int rd, int rs1, int sign,
+		       int rm, int is_32bit)
+{
+  struct riscv_sim_cpu *riscv_cpu = RISCV_SIM_CPU (cpu);
+  double src, rounded;
+  uint64_t rs1_bits;
+  int iclamp;
+  uint32_t uclamp;
+  rs1_bits = (uint64_t) riscv_cpu->fpregs[rs1];
+  memcpy (&src, &rs1_bits, sizeof (src));
+
+  if (rm == DYN)
+    rm = riscv_cpu->csr.frm;
+
+  /* Get the input rounded.  */
+  rounded = round_double_input (src, rm);
+
+  if (sign == SIGNED)
+    {
+      /* Clamp the input to int32_t range.  */
+      iclamp = min (max ((int64_t) rounded, INT_MIN), INT_MAX);
+      if (is_32bit)
+	store_rd (cpu, rd, (int) iclamp);
+      else
+	store_rd (cpu, rd, (int64_t) iclamp);
+    }
+  else
+    {
+      /* Clamp the input to uint32_t range.  */
+      uclamp = min (max ((uint64_t) rounded, 0), UINT_MAX);
+      if (rounded < 0.0f)
+	uclamp = 0;
+      if (is_32bit)
+	store_rd (cpu, rd, (uint32_t) uclamp);
+      else
+	store_rd (cpu, rd, (uint64_t) uclamp);
+    }
+}
+
+/* Convert the double precision floating point value into long integer.  */
+static void
+convert_double_to_long (SIM_CPU *cpu, int rd, int rs1, int sign,
+		       int rm)
+{
+  struct riscv_sim_cpu *riscv_cpu = RISCV_SIM_CPU (cpu);
+  double src, rounded;
+  uint64_t rs1_bits;
+  int64_t lclamp;
+  uint64_t luclamp;
+  rs1_bits = (uint64_t) riscv_cpu->fpregs[rs1];
+  memcpy (&src, &rs1_bits, sizeof (src));
+
+  if (rm == DYN)
+    rm = riscv_cpu->csr.frm;
+
+  /* Get the input rounded.  */
+  rounded = round_double_input (src, rm);
+
+  if (sign == SIGNED)
+    {
+      /* Clamp the input to int64_t range.  */
+      lclamp = min (max ((int64_t) rounded, LONG_MIN), LONG_MAX);
+      store_rd (cpu, rd, (int64_t) lclamp);
+    }
+  else
+    {
+      /* Clamp the input to uint64_t range.  */
+      luclamp = min (max ((uint64_t) rounded, 0), ULONG_MAX);
+      if (rounded < 0.0f)
+	luclamp = 0;
+      store_rd (cpu, rd, (uint64_t) luclamp);
+    }
+}
+
+/* Convert the long integer value into double precision floating point.  */
+static void
+convert_long_to_double (SIM_CPU *cpu, int rd, int rs1, int sign,
+			int rm)
+{
+  struct riscv_sim_cpu *riscv_cpu = RISCV_SIM_CPU (cpu);
+  uint64_t rd_bits;
+  uint64_t usrc = (uint64_t) riscv_cpu->regs[rs1];
+  int64_t isrc = (int64_t) riscv_cpu->regs[rs1];
+  double result = .0;
+  int old_rm;
+
+  if (rm == DYN)
+    rm = riscv_cpu->csr.frm;
+
+  old_rm = set_riscv_rounding_mode (rm);
+
+  if (rm == RMM)
+    {
+      if (sign == SIGNED)
+	{
+	  if (isrc > 0)
+	    {
+	      fesetround (FE_UPWARD);
+	      result = (double) isrc;
+	      result = ceil (result);
+	    }
+	  else
+	    {
+	      fesetround (FE_DOWNWARD);
+	      result = (double) isrc;
+	      result = floor (result);
+	    }
+	}
+      else
+	{
+	  /* Since it's unsigned, it's always positive.  */
+	  fesetround (FE_UPWARD);
+	  result = (double) usrc;
+	  result = ceil (result);
+	}
+    }
+  else
+    {
+      if (sign == SIGNED)
+	result = (double) isrc;
+      else
+	result = (double) usrc;
+
+      /* Get the result rounded.  */
+      result = round_double_output (result, rm);
+    }
+
+  /* Restore rounding mode.  */
+  fesetround (old_rm);
+
+  /* Store the result.  */
+  memcpy (&rd_bits, &result, sizeof (result));
+  store_fp (cpu, rd, rd_bits);
+}
+
+/* Convert the double precision floating point value into single precision.  */
+static void
+double_to_float (SIM_CPU *cpu, int rd, int rs1, int rm)
+{
+  struct riscv_sim_cpu *riscv_cpu = RISCV_SIM_CPU (cpu);
+  double src;
+  float result = 0;
+  int old_rm;
+  uint64_t rs1_bits;
+  uint32_t rd_bits;
+
+  if (rm == DYN)
+    rm = riscv_cpu->csr.frm;
+
+  old_rm = set_riscv_rounding_mode (rm);
+
+  rs1_bits = (uint64_t) riscv_cpu->fpregs[rs1];
+  memcpy (&src, &rs1_bits, sizeof (src));
+
+  result = (float) src;
+
+  if (rm == RMM)
+    {
+      if (is_float_halfway (result))
+	{
+	  if (result > 0)
+	    result = nextafterf (result, INFINITY);
+	  else
+	    result = nextafterf (result, -INFINITY);
+	}
+    }
+
+  /* Store result.  */
+  memcpy (&rd_bits, &result, sizeof (result));
+  store_fp (cpu, rd, rd_bits);
+
+  /* Restore rounding mode.  */
+  fesetround (old_rm);
+}
+
 static void
 convert_float_to_int (SIM_CPU *cpu, int rd, int rs1, int sign,
 		      int rm, int is_32bit)
@@ -1885,6 +2133,84 @@ execute_d (SIM_CPU *cpu, unsigned_word iw, const struct riscv_opcode *op)
     case MATCH_FSQRT_D | MASK_RM:
       float64_math (cpu, rd, rs1, rs2, 0, rm, FSQRT);
       break;
+    case MATCH_FCVT_W_D:
+    case MATCH_FCVT_W_D | MASK_RM:
+      TRACE_INSN (cpu, "fcvt.w.d %s, %s, rm=%d;", rd_name, rs1_name, rm);
+      convert_double_to_int (cpu, rd, rs1, SIGNED, rm, 1);
+      break;
+    case MATCH_FCVT_WU_D:
+    case MATCH_FCVT_WU_D | MASK_RM:
+      TRACE_INSN (cpu, "fcvt.wu.d %s, %s, rm=%d;", rd_name, rs1_name, rm);
+      convert_double_to_int (cpu, rd, rs1, UNSIGNED, rm, 1);
+      break;
+    case MATCH_FCVT_D_W:
+    case MATCH_FCVT_D_W | MASK_RM:
+      {
+	double d;
+	uint64_t rd_bits;
+	int32_t isrc;
+	TRACE_INSN (cpu, "fcvt.d.w %s, %s, rm=%d;", rd_name, rs1_name, rm);
+	isrc = (int32_t) riscv_cpu->regs[rs1];
+	d = (double) isrc;
+	memcpy (&rd_bits, &d, sizeof (d));
+	store_fp (cpu, rd, rd_bits);
+	break;
+      }
+    case MATCH_FCVT_D_WU:
+    case MATCH_FCVT_D_WU | MASK_RM:
+      {
+	double d;
+	uint64_t rd_bits;
+	uint32_t usrc;
+	TRACE_INSN (cpu, "fcvt.d.wu %s, %s, rm=%d;", rd_name, rs1_name, rm);
+	usrc = (uint32_t) riscv_cpu->regs[rs1];
+	d = (double) usrc;
+	memcpy (&rd_bits, &d, sizeof (d));
+	store_fp (cpu, rd, rd_bits);
+	break;
+      }
+    case MATCH_FCVT_L_D:
+    case MATCH_FCVT_L_D | MASK_RM:
+      TRACE_INSN (cpu, "fcvt.l.d %s, %s, rm=%d;", rd_name, rs1_name, rm);
+      RISCV_ASSERT_RV64 (cpu, "insn: %s", op->name);
+      convert_double_to_long (cpu, rd, rs1, SIGNED, rm);
+      break;
+    case MATCH_FCVT_LU_D:
+    case MATCH_FCVT_LU_D | MASK_RM:
+      TRACE_INSN (cpu, "fcvt.lu.d %s, %s, rm=%d;", rd_name, rs1_name, rm);
+      RISCV_ASSERT_RV64 (cpu, "insn: %s", op->name);
+      convert_double_to_long (cpu, rd, rs1, UNSIGNED, rm);
+      break;
+    case MATCH_FCVT_D_L:
+    case MATCH_FCVT_D_L | MASK_RM:
+      TRACE_INSN (cpu, "fcvt.d.l %s, %s, rm=%d;", rd_name, rs1_name, rm);
+      RISCV_ASSERT_RV64 (cpu, "insn: %s", op->name);
+      convert_long_to_double (cpu, rd, rs1, SIGNED, rm);
+      break;
+    case MATCH_FCVT_D_LU:
+    case MATCH_FCVT_D_LU | MASK_RM:
+      TRACE_INSN (cpu, "fcvt.d.lu %s, %s, rm=%d;", rd_name, rs1_name, rm);
+      RISCV_ASSERT_RV64 (cpu, "insn: %s", op->name);
+      convert_long_to_double (cpu, rd, rs1, UNSIGNED, rm);
+      break;
+    case MATCH_FCVT_S_D:
+    case MATCH_FCVT_S_D | MASK_RM:
+      double_to_float (cpu, rd, rs1, rm);
+      break;
+    case MATCH_FCVT_D_S:
+      {
+	float f;
+	double d;
+	uint64_t rd_bits;
+	uint32_t rs1_bits;
+	TRACE_INSN (cpu, "fcvt.d.s %s, %s;", frd_name, frs1_name);
+	rs1_bits = (uint32_t) riscv_cpu->fpregs[rs1];
+	memcpy (&f, &rs1_bits, sizeof (f));
+	d = (double) f;
+	memcpy (&rd_bits, &d, sizeof (d));
+	store_fp (cpu, rd, rd_bits);
+	break;
+      }
     default:
       TRACE_INSN (cpu, "UNHANDLED INSN: %s", op->name);
       sim_engine_halt (sd, cpu, NULL, riscv_cpu->pc, sim_signalled, SIM_SIGILL);
diff --git a/sim/testsuite/riscv/d-conversion.s b/sim/testsuite/riscv/d-conversion.s
new file mode 100755
index 00000000000..e2ca0a3e1c7
--- /dev/null
+++ b/sim/testsuite/riscv/d-conversion.s
@@ -0,0 +1,111 @@
+# Double precision conversion tests.
+# mach: riscv32 riscv64
+# sim(riscv64): --model RV64ID
+# ld(riscv64): -m elf64lriscv
+# as(riscv64): -march=rv64id
+
+.include "testutils.inc"
+
+	.section	.rodata
+	.align 3
+
+_arg1:
+	.double 123.49
+	.word 123
+	.word 0
+	.double -3e9
+	.double 2147483648.5
+	.dword 2147483647
+	.float -12.5
+	.float .0
+	.double -12.5
+
+_result:
+	.word 123
+	.word 0
+	.double 123.0
+	.dword -3000000000
+	.dword 2147483648
+	.double 2147483647
+	.double -12.5
+	.float -12.5
+
+	start
+	.option push
+	.option norelax
+	la	a0,_arg1
+	la	a1,_result
+	li	a2,1
+	.option pop
+
+	# Test fcvt.w.d instruction.
+	fld	fa0,0(a0)
+	lw	a3,0(a1)
+	fcvt.w.d	a5,fa0,rne
+	bne	a3,a5,test_fail
+
+	# Test fcvt.wu.d instruction.
+	fld	fa0,0(a0)
+	lw	a3,0(a1)
+	fcvt.wu.d	a5,fa0,rne
+	bne	a3,a5,test_fail
+
+	# Test fcvt.d.w instruction.
+	lw	a3,8(a0)
+	fld	fa0,8(a1)
+	fcvt.d.w	fa1,a3
+	feq.d	a4,fa0,fa1
+	bne	a4,a2,test_fail
+
+	# Test fcvt.d.wu instruction.
+	lw	a3,8(a0)
+	fld	fa0,8(a1)
+	fcvt.d.wu	fa1,a3
+	feq.d	a4,fa0,fa1
+	bne	a4,a2,test_fail
+
+	# Test fcvt.l.d instruction.
+	fld	fa0,16(a0)
+	ld	a3,16(a1)
+	fcvt.l.d	a5,fa0,rne
+	bne	a5,a3,test_fail
+
+	# Test fcvt.lu.d instruction.
+	fld	fa0,24(a0)
+	ld	a3,24(a1)
+	fcvt.lu.d	a5,fa0,rne
+	bne	a5,a3,test_fail
+
+	# Test fcvt.d.l instruction.
+	ld	a3,32(a0)
+	fld	fa0,32(a1)
+	fcvt.d.l	fa1,a3,rne
+	feq.d	a4,fa0,fa1
+	bne	a4,a2,test_fail
+
+	# Test fcvt.d.lu instruction.
+	ld	a3,32(a0)
+	fld	fa0,32(a1)
+	fcvt.d.lu	fa1,a3,rne
+	feq.d	a4,fa0,fa1
+	bne	a4,a2,test_fail
+
+	# Test fcvt.d.s instruction.
+	flw	fa0,40(a0)
+	fld	fa1,40(a1)
+	fcvt.d.s	fa2,fa0
+	feq.d	a4,fa2,fa1
+	bne	a4,a2,test_fail
+
+	# Test fcvt.s.d instruction.
+	fld	fa0,48(a0)
+	flw	fa1,48(a1)
+	fcvt.s.d	fa2,fa0
+	feq.s	a4,fa2,fa1
+	bne	a4,a2,test_fail
+
+test_pass:
+	pass
+
+test_fail:
+	fail
