Hello World in PowerPC Assembly (Linux)

A simple Hello World implementation in 32-bit PowerPC assembly language for Linux systems. This implementation is for traditional big-endian PowerPC systems, common in older embedded systems and classic PowerPC workstations.

Installation

On a PowerPC Linux system, you'll need the standard GNU toolchain:

sudo apt-get update
sudo apt-get install binutils gcc

Running

Assemble and link:

as -o main.o main.s -mbig -32
ld -o hello main.o
./hello

Code Explanation

The 32-bit PowerPC implementation shows several differences from its 64-bit counterpart. The architecture uses simpler addressing modes and requires less complex address loading sequences.

Key architectural features:

Memory Access:

• Uses big-endian byte ordering
• 32-bit address space simplifies address loading
• Alignment follows 32-bit (4-byte) boundaries
• Uses @ha and @l for address calculations instead of the more complex 64-bit addressing

Register Usage:

• Register 0: System call number
• Register 3: First argument (file descriptor or return code)
• Register 4: Second argument (message address)
• Register 5: Third argument (message length)

Instructions:

• li (Load Immediate): Loads a 16-bit value
• lis (Load Immediate Shifted): Loads a 16-bit value into the upper half
• la (Load Address): Combines base and displacement
• sc (System Call): Triggers kernel service

The 32-bit implementation is simpler than the 64-bit version because:

• Addresses are 32 bits instead of 64 bits
• Fewer instructions needed for address loading
• Memory alignment requirements are less strict
• No need for complex address construction sequences