python3 fixes for vgabios and csm builds.rel-1.7.5

Avoid using chr() as this produces unicode strings on python3.  Make
sure to only use ord() on slices as the python3 bytearray type returns
an integer on a non-slice array access.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 11 insertions, 7 deletions

diff --git a/scripts/buildrom.py b/scripts/buildrom.py
index 8ff60e2..0499049 100755
--- a/scripts/buildrom.py
+++ b/scripts/buildrom.py
@@ -5,7 +5,7 @@
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
 
-import sys
+import sys, struct
 
 from python23compat import as_bytes
 
@@ -14,8 +14,11 @@ def alignpos(pos, alignbytes):
     return (pos + mask) & ~mask
 
 def checksum(data):
-    ords = map(ord, data)
-    return sum(ords)
+    if (sys.version_info > (3, 0)):
+        cksum = sum(data)
+    else:
+        cksum = sum(map(ord, data))
+    return struct.pack('<B', (0x100 - cksum) & 0xff)
 
 def main():
     inname = sys.argv[1]
@@ -34,14 +37,15 @@ def main():
     # Check if a pci header is present
     pcidata = ord(data[24:25]) + (ord(data[25:26]) << 8)
     if pcidata != 0:
-        data = data[:pcidata + 16] + chr(int(count/512)) + chr(0) + data[pcidata + 18:]
+        blocks = struct.pack('<H', int(count/512))
+        data = data[:pcidata + 16] + blocks + data[pcidata + 18:]
 
     # Fill in size field; clear checksum field
-    data = data[:2] + chr(int(count/512)) + data[3:6] + as_bytes("\0") + data[7:]
+    blocks = struct.pack('<B', int(count/512))
+    data = data[:2] + blocks + data[3:6] + as_bytes("\0") + data[7:]
 
     # Checksum rom
-    newsum = (256 - checksum(data)) & 0xff
-    data = data[:6] + chr(newsum) + data[7:]
+    data = data[:6] + checksum(data) + data[7:]
 
     # Write new rom
     f = open(outname, 'wb')