CPYFPTRN, CPYFMTRN, CPYFETRN

Memory Copy Forward-only, reads and writes unprivileged, reads non-temporal. These instructions perform a memory copy. The prologue, main, and epilogue instructions are expected to be run in succession and to appear consecutively in memory: CPYFPTRN, then CPYFMTRN, and then CPYFETRN.

CPYFPTRN performs some preconditioning of the arguments suitable for using the CPYFMTRN instruction, and performs an implementation defined amount of the memory copy. CPYFMTRN performs an implementation defined amount of the memory copy. CPYFETRN performs the last part of the memory copy.

The memory copy performed by these instructions is in the forward direction only, so the instructions are suitable for a memory copy only where there is no overlap between the source and destination locations, or where the source address is greater than the destination address.

The architecture supports two algorithms for the memory copy: option A and option B. Which algorithm is used is implementation defined.

After execution of CPYFPTRN, option A (which results in encoding PSTATE.C = 0):

• If Xn<63> == 1, the copy size is saturated to 0x7FFFFFFFFFFFFFFF.
• Xs holds the original Xs + saturated Xn.
• Xd holds the original Xd + saturated Xn.
• Xn holds -1* saturated Xn + an implementation defined number of bytes copied.
• PSTATE.{N,Z,V} are set to {0,0,0}.

After execution of CPYFPTRN, option B (which results in encoding PSTATE.C = 1):

• If Xn<63> == 1, the copy size is saturated to 0x7FFFFFFFFFFFFFFF.
• Xs holds the original Xs + an implementation defined number of bytes copied.
• Xd holds the original Xd + an implementation defined number of bytes copied.
• Xn holds the saturated Xn - an implementation defined number of bytes copied.
• PSTATE.{N,Z,V} are set to {0,0,0}.

For CPYFMTRN, option A (encoded by PSTATE.C = 0), the format of the arguments is:

• Xn is treated as a signed 64-bit number and holds -1* the number of bytes remaining to be copied in the memory copy in total.
• Xs holds the lowest address that the copy is copied from -Xn.
• Xd holds the lowest address that the copy is made to -Xn.
• At the end of the instruction, the value of Xn is written back with -1* the number of bytes remaining to be copied in the memory copy in total.

For CPYFMTRN, option B (encoded by PSTATE.C = 1), the format of the arguments is:

• Xn holds the number of bytes remaining to be copied in the memory copy in total.
• Xs holds the lowest address that the copy is copied from.
• Xd holds the lowest address that the copy is copied to.
• At the end of the instruction:
  • the value of Xn is written back with the number of bytes remaining to be copied in the memory copy in total.
  • the value of Xs is written back with the lowest address that has not been copied from.
  • the value of Xd is written back with the lowest address that has not been copied to.

For CPYFETRN, option A (encoded by PSTATE.C = 0), the format of the arguments is:

• Xn is treated as a signed 64-bit number and holds -1* the number of bytes remaining to be copied in the memory copy in total.
• Xs holds the lowest address that the copy is copied from -Xn.
• Xd holds the lowest address that the copy is made to -Xn.
• At the end of the instruction, the value of Xn is written back with 0.

For CPYFETRN, option B (encoded by PSTATE.C = 1), the format of the arguments is:

• Xn holds the number of bytes remaining to be copied in the memory copy in total.
• Xs holds the lowest address that the copy is copied from.
• Xd holds the lowest address that the copy is copied to.
• At the end of the instruction:
  • the value of Xn is written back with 0.
  • the value of Xs is written back with the lowest address that has not been copied from.
  • the value of Xd is written back with the lowest address that has not been copied to.

Integer
(FEAT_MOPS)

if !HaveFeatMOPS() || sz != '00' then UNDEFINED; integer d = UInt(Rd); integer s = UInt(Rs); integer n = UInt(Rn); bits(4) options = op2; boolean rnontemporal = options<3> == '1'; boolean wnontemporal = options<2> == '1'; MOPSStage stage; case op1 of when '00' stage = MOPSStage_Prologue; when '01' stage = MOPSStage_Main; when '10' stage = MOPSStage_Epilogue; otherwise SEE "Memory Copy and Memory Set"; CheckMOPSEnabled(); if s == n || s == d || n == d || d == 31 || s == 31 || n == 31 then Constraint c = ConstrainUnpredictable(Unpredictable_MOPSOVERLAP31); assert c IN {Constraint_UNDEF, Constraint_NOP}; case c of when Constraint_UNDEF UNDEFINED; when Constraint_NOP EndOfInstruction();

Assembler Symbols