Memory Copy, writes 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: CPYPWN, then CPYMWN, and then CPYEWN.
CPYPWN performs some preconditioning of the arguments suitable for using the CPYMWN instruction, and performs an implementation defined amount of the memory copy. CPYMWN performs an implementation defined amount of the memory copy. CPYEWN performs the last part of the memory copy.
The inclusion of implementation defined amounts of memory copy allows some optimization of the size that can be performed.
For CPYPWN, the following saturation logic is applied:
If Xn<63:55> != 000000000, the copy size Xn is saturated to 0x007FFFFFFFFFFFFF.
After that saturation logic is applied, the direction of the memory copy is based on the following algorithm:
If (Xs > Xd) && (Xd + saturated Xn) > Xs, then direction = forward
Elsif (Xs < Xd) && (Xs + saturated Xn) > Xd, then direction = backward
Else direction = implementation defined choice between forward and backward.
The architecture supports two algorithms for the memory copy: option A and option B. Which algorithm is used is implementation defined.
Portable software should not assume that the choice of algorithm is constant.
After execution of CPYPWN, option A (which results in encoding PSTATE.C = 0):
After execution of CPYPWN, option B (which results in encoding PSTATE.C = 1):
For CPYMWN, option A (encoded by PSTATE.C = 0), the format of the arguments is:
For CPYMWN, option B (encoded by PSTATE.C = 1), the format of the arguments is:
For CPYEWN, option A (encoded by PSTATE.C = 0), the format of the arguments is:
For CPYEWN, option B (encoded by PSTATE.C = 1), the format of the arguments is:
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
sz | 0 | 1 | 1 | 1 | 0 | 1 | op1 | 0 | Rs | 0 | 1 | 0 | 0 | 0 | 1 | Rn | Rd | ||||||||||||||
op2 |
if !HaveFeatMOPS() then UNDEFINED; if sz != '00' then UNDEFINED; integer d = UInt(Rd); integer s = UInt(Rs); integer n = UInt(Rn); bits(4) options = op2; 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 c = ConstrainUnpredictable(Unpredictable_MOPSOVERLAP31); assert c IN {Constraint_UNDEF, Constraint_NOP}; case c of when Constraint_UNDEF UNDEFINED; when Constraint_NOP EndOfInstruction();
integer N = MaxBlockSizeCopiedBytes(); bits(64) toaddress = X[d, 64]; bits(64) fromaddress = X[s, 64]; bits(64) cpysize = X[n, 64]; bits(4) nzcv = PSTATE.<N,Z,C,V>; bits(64) stagecpysize; bits(8*N) readdata; integer B; boolean supports_option_a = CPYOptionA(); boolean rprivileged; boolean wprivileged; case PSTATE.EL of when EL0 rprivileged = FALSE; wprivileged = FALSE; when EL1 if EL2Enabled() && HaveNVExt() && HCR_EL2.<NV,NV1> == '11' then rprivileged = TRUE; wprivileged = TRUE; else rprivileged = options<1> == '0'; wprivileged = options<0> == '0'; when EL2 if HaveVirtHostExt() && HCR_EL2.<E2H,TGE> == '11' then rprivileged = options<1> == '0'; wprivileged = options<0> == '0'; else rprivileged = TRUE; wprivileged = TRUE; when EL3 rprivileged = TRUE; wprivileged = TRUE; if HaveUAOExt() && PSTATE.UAO == '1' then rprivileged = PSTATE.EL != EL0; wprivileged = PSTATE.EL != EL0; boolean rnontemporal = options<3> == '1'; boolean wnontemporal = options<2> == '1'; AccessDescriptor raccdesc = CreateAccDescMOPS(MemOp_LOAD, rprivileged, rnontemporal); AccessDescriptor waccdesc = CreateAccDescMOPS(MemOp_STORE, wprivileged, wnontemporal); if stage == MOPSStage_Prologue then if cpysize<63:55> != '000000000' then cpysize = 0x007FFFFFFFFFFFFF<63:0>; boolean forward; if ((UInt(fromaddress<55:0>) > UInt(toaddress<55:0>)) && (UInt(fromaddress<55:0>) < UInt(toaddress<55:0> + cpysize<55:0>))) then forward = TRUE; elsif ((UInt(fromaddress<55:0>) < UInt(toaddress<55:0>)) && (UInt(fromaddress<55:0> + cpysize<55:0>) > UInt(toaddress<55:0>))) then forward = FALSE; else forward = MemCpyDirectionChoice(fromaddress, toaddress, cpysize); if supports_option_a then nzcv = '0000'; if forward then // Copy in the forward direction offsets the arguments. toaddress = toaddress + cpysize; fromaddress = fromaddress + cpysize; cpysize = Zeros(64) - cpysize; else if !forward then // Copy in the reverse direction offsets the arguments. toaddress = toaddress + cpysize; fromaddress = fromaddress + cpysize; nzcv = '1010'; else nzcv = '0010'; // IMP DEF selection of the amount covered by pre-processing. stagecpysize = CPYPreSizeChoice(toaddress, fromaddress, cpysize); assert stagecpysize<63> == cpysize<63> || stagecpysize == Zeros(64); if SInt(cpysize) > 0 then assert SInt(stagecpysize) <= SInt(cpysize); else assert SInt(stagecpysize) >= SInt(cpysize); else boolean zero_size_exceptions = MemCpyZeroSizeCheck(); // Check if this version is consistent with the state of the call. if zero_size_exceptions || SInt(cpysize) != 0 then if supports_option_a then if nzcv<1> == '1' then // PSTATE.C boolean wrong_option = TRUE; boolean from_epilogue = stage == MOPSStage_Epilogue; MismatchedMemCpyException(supports_option_a, d, s, n, wrong_option, from_epilogue, options); else if nzcv<1> == '0' then // PSTATE.C boolean wrong_option = TRUE; boolean from_epilogue = stage == MOPSStage_Epilogue; MismatchedMemCpyException(supports_option_a, d, s, n, wrong_option, from_epilogue, options); bits(64) postsize = CPYPostSizeChoice(toaddress, fromaddress, cpysize); assert postsize<63> == cpysize<63> || SInt(postsize) == 0; if stage == MOPSStage_Main then stagecpysize = cpysize - postsize; // Check if the parameters to this instruction are valid. if MemCpyParametersIllformedM(toaddress, fromaddress, cpysize) then boolean wrong_option = FALSE; boolean from_epilogue = FALSE; MismatchedMemCpyException(supports_option_a, d, s, n, wrong_option, from_epilogue, options); else stagecpysize = postsize; // Check if the parameters to the epilogue are valid. if (cpysize != postsize || MemCpyParametersIllformedE(toaddress, fromaddress, cpysize)) then boolean wrong_option = FALSE; boolean from_epilogue = TRUE; MismatchedMemCpyException(supports_option_a, d, s, n, wrong_option, from_epilogue, options); if supports_option_a then while SInt(stagecpysize) != 0 do // IMP DEF selection of the block size that is worked on. While many // implementations might make this constant, that is not assumed. B = CPYSizeChoice(toaddress, fromaddress, cpysize); if SInt(cpysize) < 0 then assert B <= -1 * SInt(stagecpysize); readdata<B*8-1:0> = Mem[fromaddress+cpysize, B, raccdesc]; Mem[toaddress+cpysize, B, waccdesc] = readdata<B*8-1:0>; cpysize = cpysize + B; stagecpysize = stagecpysize + B; else assert B <= SInt(stagecpysize); cpysize = cpysize - B; stagecpysize = stagecpysize - B; readdata<B*8-1:0> = Mem[fromaddress+cpysize, B, raccdesc]; Mem[toaddress+cpysize, B, waccdesc] = readdata<B*8-1:0>; if stage != MOPSStage_Prologue then X[n, 64] = cpysize; else while UInt(stagecpysize) > 0 do // IMP DEF selection of the block size that is worked on. While many // implementations might make this constant, that is not assumed. B = CPYSizeChoice(toaddress, fromaddress, cpysize); assert B <= UInt(stagecpysize); if nzcv<3> == '0' then // PSTATE.N readdata<B*8-1:0> = Mem[fromaddress, B, raccdesc]; Mem[toaddress, B, waccdesc] = readdata<B*8-1:0>; fromaddress = fromaddress + B; toaddress = toaddress + B; else readdata<B*8-1:0> = Mem[fromaddress-B, B, raccdesc]; Mem[toaddress-B, B, waccdesc] = readdata<B*8-1:0>; fromaddress = fromaddress - B; toaddress = toaddress - B; cpysize = cpysize - B; stagecpysize = stagecpysize - B; if stage != MOPSStage_Prologue then X[n, 64] = cpysize; X[d, 64] = toaddress; X[s, 64] = fromaddress; if stage == MOPSStage_Prologue then X[n, 64] = cpysize; X[d, 64] = toaddress; X[s, 64] = fromaddress; PSTATE.<N,Z,C,V> = nzcv;
Internal version only: isa v33.53, AdvSIMD v29.11, pseudocode v2022-09_rel, sve v2022-09_rel ; Build timestamp: 2022-09-30T16:37
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