VFPv3D16

VFPv3D16 is a configuration designation for ARM’s Vector Floating Point unit (VFP). The label indicates a VFP version 3 core with a 16-double-precision register bank. In this setup, the processor provides 16 64-bit double-precision registers (D0–D15) and, through pairing, 32 single-precision registers (S0–S31). This arrangement is common on several ARM cores that implement VFPv3 but do not expose the larger 32-double-precision register bank.

The VFPv3 instruction set supports a range of floating-point operations in both single- and double-precision formats, including arithmetic, data movement, comparisons, and conversions between integer and floating-point types. Instructions are accessed through the ARM instruction flow and are typically enabled via the VFP coprocessors CP10/CP11 and the appropriate FP enable bits in the program status register. The D16 configuration emphasizes a smaller, lower-power register bank while still delivering the core floating-point functionality needed by many mobile and embedded applications.

In software, VFPv3D16 is commonly reflected in CPU feature strings and runtime checks on Linux and other operating systems. Compilers with VFP support generate FP code that targets this VFP variant when the corresponding feature flag is present. Performance characteristics depend on the specific core implementation and clock, but VFPv3D16 generally provides adequate floating-point throughput for typical mobile workloads without the broader register footprint of larger VFP configurations.

Compared with configurations that expose more double-precision registers (such as larger D32 variants) or with architectures that rely on NEON for vector performance, VFPv3D16 represents a compact, widely supported floating-point option within the ARMv7-A family and similar cores. See also VFP, ARM architecture, and NEON.