diff --git a/reactos/tools/rsym/rsym64.c b/reactos/tools/rsym/rsym64.c
index aba6e2b6197..cfb12fcbb5e 100644
--- a/reactos/tools/rsym/rsym64.c
+++ b/reactos/tools/rsym/rsym64.c
@@ -557,7 +557,7 @@ GeneratePData(PFILE_INFO File)
 
     /* Allocate .pdata buffer */
     pdata = File->pdata.p = malloc(pshp->SizeOfRawData);
-    memset(File->pdata.p, pshp->SizeOfRawData, 0);
+    memset(File->pdata.p, 0, pshp->SizeOfRawData,);
 
     /* Init exception data dir */
     Dir = &File->OptionalHeader->DataDirectory[IMAGE_DIRECTORY_ENTRY_EXCEPTION];
@@ -581,7 +581,7 @@ GeneratePData(PFILE_INFO File)
 
     /* Allocate .xdata buffer */
     File->xdata.p = malloc(pshx->SizeOfRawData);
-    memset(File->xdata.p, pshx->SizeOfRawData, 0);
+    memset(File->xdata.p, 0, pshx->SizeOfRawData);
 
     i = 0;
     Offset = File->eh_frame.psh->VirtualAddress;
@@ -890,7 +890,7 @@ int main(int argc, char* argv[])
     }
 
     File.AlignBuf = malloc(File.OptionalHeader->FileAlignment);
-    memset(File.AlignBuf, File.OptionalHeader->FileAlignment, 0);
+    memset(File.AlignBuf, 0, File.OptionalHeader->FileAlignment);
 
     GeneratePData(&File);