diff --git a/src/Makefile b/src/Makefile
index 9feb5c6..95190ab 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -4,7 +4,7 @@ NAME = z80test
 VERSION = 1.1a
 PKG := $(NAME)-$(VERSION)
 
-PROGS := z80full z80flags z80doc z80docflags z80ccf z80memptr
+PROGS := z80full z80flags z80doc z80docflags z80ccf z80memptr z80ccfscr
 SRCS  := main idea crctab tests testmacros print
 
 all: $(addsuffix .tap,$(PROGS))
diff --git a/src/z80ccfscr.asm b/src/z80ccfscr.asm
new file mode 100644
index 0000000..d19b3c3
--- /dev/null
+++ b/src/z80ccfscr.asm
@@ -0,0 +1,32 @@
+; Z80 test - monitor random behavior of bits 5 and 3 after CCF.
+;
+; Copyright (C) 2022 Patrik Rak (patrik@raxoft.cz)
+;
+; This source code is released under the MIT license, see included license.txt.
+
+            org     0x8000
+
+main:       di
+            ld      sp,22528+512
+            ld      hl,0x7838
+            ld      b,0
+.fill       push    hl
+            djnz    .fill
+            ld      sp,49152
+            ld      hl,16384
+            ld      d,0xEF
+.loop       push    hl
+            pop     af
+            ccf
+            push    af
+            pop     bc
+            ld      a,l
+            xor     c
+            ld      (hl),a
+            inc     hl
+            ld      a,h
+            and     d
+            ld      h,a
+            jp      .loop
+
+; EOF ;