Why does the x86 have so few registers?

Raymond Chen January 5, 2004 Jan 5, 2004 01/5/04

One of the comments to my discussion of 16-bit calling conventions wondered why the 8086 had so few registers. The 8086 was a 16-bit version of the even older 8080 processor, which had six 8-bit registers, named A, B, C, D, E, H, and L. The registers could be used in pairs to products three 16-bit pseudo-registers, BC, DE, and HL. What's more...

The history of calling conventions, part 1

Raymond Chen January 2, 2004 Jan 2, 2004 01/2/04

The great thing about calling conventions on the x86 platform is that there are so many to choose from! In the 16-bit world, part of the calling convention was fixed by the instruction set: The BP register defaults to the SS selector, whereas the other registers default to the DS selector. So the BP register was necessarily the register used ...