(old) | htmldiff from- | (new) |
Load Pair of SIMD&FP registers. This instruction loads a pair of SIMD&FP registers from memory. The address that is used for the load is calculated from a base register value and an optional immediate offset.
Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.
It has encodings from 3 classes: Post-index , Pre-index and Signed offset
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 |
opc | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | imm7 | Rt2 | Rn | Rt | |||||||||||||||||||
L |
boolean wback = TRUE; boolean postindex = TRUE;
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 |
opc | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | imm7 | Rt2 | Rn | Rt | |||||||||||||||||||
L |
boolean wback = TRUE; boolean postindex = FALSE;
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 |
opc | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | imm7 | Rt2 | Rn | Rt | |||||||||||||||||||
L |
boolean wback = FALSE; boolean postindex = FALSE;
For information about the constrained unpredictable behavior of this instruction, see Architectural Constraints on UNPREDICTABLE behaviors, and particularly LDP (SIMD&FP).
<Dt1> | Is the 64-bit name of the first SIMD&FP register to be transferred, encoded in the "Rt" field. |
<Dt2> | Is the 64-bit name of the second SIMD&FP register to be transferred, encoded in the "Rt2" field. |
<Qt1> | Is the 128-bit name of the first SIMD&FP register to be transferred, encoded in the "Rt" field. |
<Qt2> | Is the 128-bit name of the second SIMD&FP register to be transferred, encoded in the "Rt2" field. |
<St1> | Is the 32-bit name of the first SIMD&FP register to be transferred, encoded in the "Rt" field. |
<St2> | Is the 32-bit name of the second SIMD&FP register to be transferred, encoded in the "Rt2" field. |
<Xn|SP> | Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field. |
integer n = UInt(Rn);
integer t = UInt(Rt);
integer t2 = UInt(Rt2);
if opc == '11' then UNDEFINED;
integer scale = 2 +(Rt2); AccType acctype = AccType_VEC;
MemOp memop = if L == '1' then MemOp_LOAD else MemOp_STORE;
if opc == '11' then UNDEFINED;
integer scale = 2 + UInt(opc);
integer datasize = 8 << scale;
bits(64) offset = LSL(SignExtend(imm7, 64), scale);
boolean tag_checked = wback || n != 31;
CheckFPAdvSIMDEnabled64();
bits(64) address;
bits(datasize) data1;
bits(datasize) data2;
constant integer dbytes = datasize DIV 8;
boolean rt_unknown = FALSE;
if HaveMTEExt() then
SetNotTagCheckedInstruction(!tag_checked);
if t == t2 thenif memop ==
MemOp_LOAD && t == t2 then
Constraint c = ConstrainUnpredictable(Unpredictable_LDPOVERLAP);
assert c IN {Constraint_UNKNOWN, Constraint_UNDEF, Constraint_NOP};
case c of
when Constraint_UNKNOWN rt_unknown = TRUE; // result is UNKNOWN
when Constraint_UNDEF UNDEFINED;
when Constraint_NOP EndOfInstruction();
if n == 31 then
CheckSPAlignment();
address = SP[];
else
address = X[n];
if !postindex then
if ! postindex then
address = address + offset;
data1 =case memop of
when MemOp_STORE
data1 = V[t];
data2 = V[t2];
Mem[address, dbytes,[address + 0 , dbytes, acctype] = data1; AccType_VECMem];
data2 =[address + dbytes, dbytes, acctype] = data2;
when MemOp_LOAD
data1 = Mem[address+dbytes, dbytes,[address + 0 , dbytes, acctype];
data2 = AccType_VECMem];
if rt_unknown then
data1 = bits(datasize) UNKNOWN;
data2 = bits(datasize) UNKNOWN;[address + dbytes, dbytes, acctype];
if rt_unknown then
data1 = bits(datasize) UNKNOWN;
data2 = bits(datasize) UNKNOWN;
V[t] = data1;
V[t2] = data2;
if wback then
if postindex then
address = address + offset;
if n == 31 then
SP[] = address;
else
X[n] = address;
If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.
Internal version only: isa v30.44, AdvSIMD v27.08, pseudocode v8.5-2019-06_rc2-5-g22901f2, sve v2019-06_rc4
; Build timestamp: 2019-06-26T22:3004
Copyright © 2010-2019 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.
(old) | htmldiff from- | (new) |