s390x

This article describes some notes about z/Architecture with a focus on the ELF ABI and ELF linkers. An lld/ELF patch sparked my motivation to study the architecture and write this post.

z/Architecture is a big-endian mainframe computer architecture supporting 24-bit, 31-bit, and 64-bit addressing modes. It is the latest generation in a lineage stretching back to the 1964 with IBM System/360 (32-bit general-purpose registers and 24-bit addressing). This lineage includes System/370 (1970), System/370 Extended Architecture (1983), Enterprise Systems Architecture/370 (1988), and Enterprise Systems Architecture/390 (1990). For a deeper dive into the design choices behind z/Architecture's extension from ESA/390, you can refer to "Development and attributes of z/Architecture."