diff --git a/tb/pcie.py b/tb/pcie.py
index 3491f5d60..f350b8c18 100644
--- a/tb/pcie.py
+++ b/tb/pcie.py
@@ -1327,7 +1327,7 @@ class MSICapability(object):
             # Mask bits
             self.msi_mask_bits = byte_mask_update(self.msi_mask_bits, mask, data) & 0xffffffff
 
-    def issue_msi_interrupt(self, number=0, attr=0):
+    def issue_msi_interrupt(self, number=0, attr=0, tc=0):
         if not self.msi_enable:
             print("MSI disabled")
             return
@@ -1335,16 +1335,8 @@ class MSICapability(object):
             print("MSI message number out of range")
             return
 
-        tlp = TLP()
-        tlp.fmt_type = TLP_MEM_WRITE
-        tlp.requester_id = self.get_id()
-        tlp.attr = attr
-        addr = self.msi_message_address
-        if addr > 0xffffffff:
-            tlp.fmt_type = TLP_MEM_WRITE_64
-        tlp.data = [self.msi_message_data & ~(2**self.msi_multiple_message_enable-1) | number]
-        tlp.set_be(addr, 4)
-        yield self.send(tlp)
+        data = self.msi_message_data & ~(2**self.msi_multiple_message_enable-1) | number
+        yield self.mem_write(self.msi_message_address, struct.pack('<L', data), attr=attr, tc=tc)
 
 
 class MSIXCapability(object):
@@ -1398,20 +1390,12 @@ class MSIXCapability(object):
             if mask & 0x8: self.msix_function_mask = (data & 1 << 30 != 0)
             if mask & 0x8: self.msix_enable = (data & 1 << 31 != 0)
 
-    def issue_msix_interrupt(self, addr, data, attr=0):
+    def issue_msix_interrupt(self, addr, data, attr=0, tc=0):
         if not self.msix_enable:
             print("MSI-X disabled")
             return
 
-        tlp = TLP()
-        tlp.fmt_type = TLP_MEM_WRITE
-        tlp.requester_id = self.get_id()
-        tlp.attr = attr
-        if addr > 0xffffffff:
-            tlp.fmt_type = TLP_MEM_WRITE_64
-        tlp.data = [data]
-        tlp.set_be(addr, 4)
-        yield self.send(tlp)
+        yield self.mem_write(addr, struct.pack('<L', data), attr=attr, tc=tc)
 
 
 class Function(PMCapability, PCIECapability):