Registers in computer hardware are rapid, direct hardware access in computation. C register variables in general are stored in registers as well.
Here are some reason why we use registers in computation,
- to hold temporary results
- can reduce use of stack memory
- make computation faster
Number of registers
The SPARC processor usually contains as many as 160 general purpose registers. According to the "Oracle SPARC Architecture 2015" specification an implementation may contain from 72 to 640 general-purpose 64-bit registers. On the chip itself, there are 63 physical 32-bit floating point registers, the 64-bit double value registers are layered on top of those.
Available Registers to users/programmers
32 registers into 4 sets,
Windowed r Registers
Initial Register Concept - p5 SPARC Registers - p51
SPARC V9 doc