Working With Data

In T32, data movement is half the story. Since there is only one general-purpose register, it helps to get comfortable with the flow between A, DP, memory, and the stack.

Reading and writing memory

The pair LDA and STA are your basic memory tools.

    LDP value
    LDA
    ADI 1
    STA

This sequence:

1. points DP at value
2. loads mem[DP] into A
3. adds 1
4. stores the result back into memory

Walking through memory

Use IDP and DDP to move the data pointer.

    LDP buffer
    LDA
    IDP
    LDA

This reads two adjacent bytes from memory.

Immediate values

Use immediate instructions when the value is known directly in the code:

• LDI imm8
• ADI imm8
• SBI imm8
• CMI imm8

These are often the simplest way to bring constants into a program.

Splitting and rebuilding DP

T32 lets you inspect or modify the low and high bytes of DP:

• LDL: copy A into the low byte of DP
• LDH: copy A into the high byte of DP
• SDL: copy the low byte of DP into A
• SDH: copy the high byte of DP into A

This is useful when you need to compute an address in pieces.

Bitwise operations

T32 includes a compact set of bitwise tools:

• AND
• ORR
• XOR
• SHL
• SHR

These all operate through A, usually using mem[DP] as the second operand for the binary operations.