R30(LR)16 Link Register stores return address of subroutine call when Branch withLinkinstructionsareperformedARM032019/3/3
R30 (LR) ARM03 2019/3/3 16 Link Register stores return address of subroutine call when Branch with Link instructions are performed
SPSP(stack-pointer)registerpointstostacktopWSPistheleastsignificant32-bitsversion Stack is full-descending: in a push the stack pointer is decremented Stack pointer alignment to a 16-byte boundary is configurable at EL1high addressSPstack inmemorylow addressARM032019/3/3
SP ARM03 2019/3/3 17 SP (stack-pointer) register points to stack top WSP is the least significant 32-bits version Stack is full-descending: in a push the stack pointer is decremented Stack pointer alignment to a 16-byte boundary is configurable at EL1 high address low address SP stack in memory
PC18PCholdingtheaddressof currentinstruction Software cannot directly write to PCItcanonlybeupdatedonabranch,exceptionentryorreturn Execute an A64instruction that is not word-aligned generates analignment faultARM032019/3/3
PC ARM03 2019/3/3 18 PC holding the address of current instruction Software cannot directly write to PC It can only be updated on a branch, exception entry or return Execute an A64 instruction that is not word-aligned generates an alignment fault
VO-V311932128-bitSIMDandFPregisters Eachregistercanbe accessed as:scalar,elementintheLSBsoftheregister■Q0-Q31,D0-D31,S0-S31,HO-H31,B0-B3164-bit vector ofbyte,halfword,or word elementsVn(.1D, .2S, .4H, .8B)128-bitvector of byte,halfword,word or doublewordVn(.2D, .4S, .8H, .16B)ARM032019/3/3
V0-V31 ARM03 2019/3/3 19 32 128-bit SIMD and FP registers Each register can be accessed as: scalar, element in the LSBs of the register ◼ Q0-Q31, D0-D31, S0-S31, H0-H31, B0-B31 64-bit vector of byte, halfword, or word elements ◼ Vn{.1D, .2S, .4H, .8B} 128-bit vector of byte, halfword, word or doubleword ◼ Vn{.2D, .4S, .8H, .16B}
FPCR,FPSR20 Two SIMD&FP control andstatusregistersARM032019/3/3
FPCR, FPSR ARM03 2019/3/3 20 Two SIMD & FP control and status registers