Predeclared extension register names in AArch32 state
You can write the names of Advanced SIMD and floating-point registers either in upper case or lower case.
The following table shows the predeclared extension register names:
Table 3-3 Predeclared extension registers in AArch32 state
||Advanced SIMD quadword registers|
||Advanced SIMD doubleword registers, floating-point double-precision registers|
||Floating-point single-precision registers|
You can write the register names either in upper case or lower case.