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