diff --git a/doc/base64.md b/doc/base64.md
new file mode 100644
index 0000000..9305165
--- /dev/null
+++ b/doc/base64.md
@@ -0,0 +1,32 @@
+# Implementing BASE64 in Z80 Assembler
+
+## About
+
+Goal of this little project is to encode and decode a byte buffer in memory. The project defines
+the following requirements.
+
+1. The function takes the pointer to an input buffer as a parameter on the stack?
+   Can also be in one of the automatic variables.
+2. Another variable contains the address of the 2nd buffer.
+3. We need to find a way to get the addresses of a DIM variable on the stack, in order to call it
+   from BASIC.
+4. Implement a subroutine for encoding a string.
+5. Implement a subroutine for decding  a string.
+
+## Problem No. 1: Splitting 3-8bit values into 4 6-bit-values.
+
+Example:
+
+We want to convert the string "ABC". In binary the values are as follows.
+
+- 01000001
+- 01000010
+- 01000011
+
+The first step is to reduce the first byte to 6 bytes:
+
+```Assembler
+        LD A,(HL)
+        SLA,2
+        PUSH A
+```