diff --git a/src/GF/Text/CP1251.hs b/src/GF/Text/CP1251.hs
index af5c829a2..7c277abab 100644
--- a/src/GF/Text/CP1251.hs
+++ b/src/GF/Text/CP1251.hs
@@ -4,15 +4,71 @@ import Data.Char
 
 decodeCP1251 = map convert where
   convert c
-   | c >= '\192' && c <= '\255' = chr (ord c + 848)
-   | c == '\168'                = chr 1025      -- cyrillic capital letter lo
-   | c == '\184'                = chr 1105      -- cyrillic small   letter lo
+   | c >= '\xC0' && c <= '\xFF' = chr (ord c + (0x410-0xC0))
+   | c == '\xA8'                = chr 0x401      -- cyrillic capital letter lo
+   | c == '\x80'                = chr 0x402
+   | c == '\x81'                = chr 0x403
+   | c == '\xAA'                = chr 0x404
+   | c == '\xBD'                = chr 0x405
+   | c == '\xB2'                = chr 0x406
+   | c == '\xAF'                = chr 0x407
+   | c == '\xA3'                = chr 0x408
+   | c == '\x8A'                = chr 0x409
+   | c == '\x8C'                = chr 0x40A
+   | c == '\x8E'                = chr 0x40B
+   | c == '\x8D'                = chr 0x40C
+   | c == '\xA1'                = chr 0x40E
+   | c == '\x8F'                = chr 0x40F
+   | c == '\xB8'                = chr 0x451      -- cyrillic small   letter lo
+   | c == '\x90'                = chr 0x452
+   | c == '\x83'                = chr 0x453
+   | c == '\xBA'                = chr 0x454
+   | c == '\xBE'                = chr 0x455
+   | c == '\xB3'                = chr 0x456
+   | c == '\xBF'                = chr 0x457
+   | c == '\xBC'                = chr 0x458
+   | c == '\x9A'                = chr 0x459
+   | c == '\x9C'                = chr 0x45A
+   | c == '\x9E'                = chr 0x45B
+   | c == '\x9D'                = chr 0x45C
+   | c == '\xA2'                = chr 0x45E
+   | c == '\x9F'                = chr 0x45F
+   | c == '\xA5'                = chr 0x490
+   | c == '\xB4'                = chr 0x491
    | otherwise                  = c
 
 encodeCP1251 = map convert where
   convert c
-   | oc >= 1040 && oc <= 1103 = chr (oc - 848)
-   | oc == 1025               = chr 168         -- cyrillic capital letter lo
-   | oc == 1105               = chr 184         -- cyrillic small   letter lo
-   | otherwise                = c
+   | oc >= 0x410 && oc <= 0x44F = chr (oc - (0x410-0xC0))
+   | oc == 0x401                = '\xA8'         -- cyrillic capital letter lo
+   | oc == 0x402                = '\x80'
+   | oc == 0x403                = '\x81'
+   | oc == 0x404                = '\xAA'
+   | oc == 0x405                = '\xBD'
+   | oc == 0x406                = '\xB2'
+   | oc == 0x407                = '\xAF'
+   | oc == 0x408                = '\xA3'
+   | oc == 0x409                = '\x8A'
+   | oc == 0x40A                = '\x8C'
+   | oc == 0x40B                = '\x8E'
+   | oc == 0x40C                = '\x8D'
+   | oc == 0x40E                = '\xA1'
+   | oc == 0x40F                = '\x8F'
+   | oc == 0x451                = '\xB8'         -- cyrillic small   letter lo
+   | oc == 0x452                = '\x90'
+   | oc == 0x453                = '\x83'
+   | oc == 0x454                = '\xBA'
+   | oc == 0x455                = '\xBE'
+   | oc == 0x456                = '\xB3'
+   | oc == 0x457                = '\xBF'
+   | oc == 0x458                = '\xBC'
+   | oc == 0x459                = '\x9A'
+   | oc == 0x45A                = '\x9C'
+   | oc == 0x45B                = '\x9E'
+   | oc == 0x45C                = '\x9D'
+   | oc == 0x45E                = '\xA2'
+   | oc == 0x45F                = '\x9F'
+   | oc == 0x490                = '\xA5'
+   | oc == 0x491                = '\xB4'
+   | otherwise                  = c
    where oc = ord c