diff --git a/libsrc/common/Makefile b/libsrc/common/Makefile
index e912795f7..381742fdf 100644
--- a/libsrc/common/Makefile
+++ b/libsrc/common/Makefile
@@ -99,9 +99,7 @@ S_OBJS = 	_cwd.o          \
 		atexit.o  	\
 		atoi.o	  	\
 		calloc.o  	\
-                cc65_cos.o      \
-                cc65_sin.o      \
-                cc65_sintab.o   \
+                cc65_sincos.o   \
                 chdir.o         \
 		copydata.o	\
                 creat.o         \
diff --git a/libsrc/common/cc65_cos.s b/libsrc/common/cc65_cos.s
deleted file mode 100644
index 06a59af35..000000000
--- a/libsrc/common/cc65_cos.s
+++ /dev/null
@@ -1,48 +0,0 @@
-;
-; Fixed point cosine function.
-;
-; Returns the cosine for the given argument as angular degree.
-; Valid argument range is 0..360
-;
-;
-; Ullrich von Bassewitz, 2009-10-29
-;
-
-        .export         _cc65_cos
-
-        .import         _cc65_sin
-
-
-
-; ---------------------------------------------------------------------------
-;
-
-.code
-
-.proc   _cc65_cos         
-
-; cos(x) = sin(x+90)
-
-        clc
-        adc     #90
-        bcc     L1
-        inx
-
-; If x is now larger than 360, we need to subtract 360.
-
-L1:     cpx     #>360
-        bne     L2
-        cmp     #<360
-L2:     bcc     L4
-
-        sbc     #<360
-        bcs     L3
-        dex
-L3:     dex
-
-L4:     jmp     _cc65_sin
-
-
-.endproc
-
-
diff --git a/libsrc/common/cc65_sin.s b/libsrc/common/cc65_sincos.s
similarity index 51%
rename from libsrc/common/cc65_sin.s
rename to libsrc/common/cc65_sincos.s
index 6d83086cf..d0b108297 100644
--- a/libsrc/common/cc65_sin.s
+++ b/libsrc/common/cc65_sincos.s
@@ -1,24 +1,74 @@
 ;
-; Fixed point sine function.
+; Fixed point cosine/sine functions.
 ;
-; Returns the cosine for the given argument as angular degree.
-; Valid argument range is 0..360
+; Returns the cosine/sine for the given argument as angular degree.
+; Valid argument range is 0..360 for both functions. They will return
+; garbage if the argument is not in a valid range. Result is in 8.8 fixed
+; point format, so $100 is 1.0 and $FF00 is -1.0.
 ;
 ;
 ; Ullrich von Bassewitz, 2009-10-29
 ;
 
-        .export         _cc65_sin
-
-        .import         _cc65_sintab
+        .export         _cc65_cos, _cc65_sin
 
 
 ; ---------------------------------------------------------------------------
-;
+; Sinus table covering values from 0..86° as 0.8 fixed point values. Values
+; for 87..90° are actually 1.0 (= $100), will therefore not fit in the table
+; and are covered specially in the code below.
+
+.rodata
+
+_cc65_sintab:
+        .byte   $00, $04, $09, $0D, $12, $16, $1B, $1F, $24, $28
+        .byte   $2C, $31, $35, $3A, $3E, $42, $47, $4B, $4F, $53
+        .byte   $58, $5C, $60, $64, $68, $6C, $70, $74, $78, $7C
+        .byte   $80, $84, $88, $8B, $8F, $93, $96, $9A, $9E, $A1
+        .byte   $A5, $A8, $AB, $AF, $B2, $B5, $B8, $BB, $BE, $C1
+        .byte   $C4, $C7, $CA, $CC, $CF, $D2, $D4, $D7, $D9, $DB
+        .byte   $DE, $E0, $E2, $E4, $E6, $E8, $EA, $EC, $ED, $EF
+        .byte   $F1, $F2, $F3, $F5, $F6, $F7, $F8, $F9, $FA, $FB
+        .byte   $FC, $FD, $FE, $FE, $FF, $FF, $FF
+
+
+
+; ---------------------------------------------------------------------------
+; Cosine function. Is actually implemented as cos(x) = sin(x+90)
 
 .code
 
-.proc   _cc65_sin
+_cc65_cos:
+
+; cos(x) = sin(x+90)
+
+        clc
+        adc     #90
+        bcc     @L1
+        inx
+
+; If x is now larger than 360, we need to subtract 360.
+
+@L1:    cpx     #>360
+        bne     @L2
+        cmp     #<360
+@L2:    bcc     _cc65_sin
+
+        sbc     #<360
+        bcs     @L3
+        dex
+@L3:    dex
+
+; ---------------------------------------------------------------------------
+; Sine function. Uses
+;
+;       table lookup            for 0..89°
+;       sin(x) = sin(180-x)     for 90°..179°
+;       sin(x) = -sin(x-180)    for 180..360°
+;
+; Plus special handling for the values missing in the table.
+
+_cc65_sin:
 
 ; If the high byte is non zero, argument is > 255
 
@@ -108,6 +158,4 @@ L6:     tay
         inx
 L7:     rts
 
-.endproc
-
 
diff --git a/libsrc/common/cc65_sintab.s b/libsrc/common/cc65_sintab.s
deleted file mode 100644
index 88464817a..000000000
--- a/libsrc/common/cc65_sintab.s
+++ /dev/null
@@ -1,24 +0,0 @@
-;
-; Sinus table
-;
-; Ullrich von Bassewitz, 2009-10-29
-;
-
-        .export         _cc65_sintab
-
-
-; ---------------------------------------------------------------------------
-;
-
-.rodata
-
-_cc65_sintab:
-        .byte   $00, $04, $09, $0D, $12, $16, $1B, $1F, $24, $28
-        .byte   $2C, $31, $35, $3A, $3E, $42, $47, $4B, $4F, $53
-        .byte   $58, $5C, $60, $64, $68, $6C, $70, $74, $78, $7C
-        .byte   $80, $84, $88, $8B, $8F, $93, $96, $9A, $9E, $A1
-        .byte   $A5, $A8, $AB, $AF, $B2, $B5, $B8, $BB, $BE, $C1
-        .byte   $C4, $C7, $CA, $CC, $CF, $D2, $D4, $D7, $D9, $DB
-        .byte   $DE, $E0, $E2, $E4, $E6, $E8, $EA, $EC, $ED, $EF
-        .byte   $F1, $F2, $F3, $F5, $F6, $F7, $F8, $F9, $FA, $FB
-        .byte   $FC, $FD, $FE, $FE, $FF, $FF, $FF