ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Common Memory System Architecture Features
return value;
// Assignment form
MemU_with_priv[bits(32) address, integer size, boolean privileged] = bits(8*size) value
// Legacy non alignment-checking configuration forces access to be aligned
if SCTLR.A == ‘0’ && SCTLR.U == ‘0’ then address = Align(address, size);
// Do aligned access, take alignment fault, or do sequence of bytes
if address == Align(address, size) then
MemA_with_priv[address, value, privileged] = value;
elsif SCTLR.A == ‘1’ then
AlignmentFault(address, TRUE);
else // if unaligned access, SCTLR.A == ‘0’, and SCTLR.U == ‘1’
if CPSR.E == ‘1’ then
value = BigEndianReverse(value, size);
for i = 0 to size-1
MemA_with_priv[address+i, 1, privileged] = value;
return;
B2.4.6 Reverse endianness
The following pseudocode describes the operation to reverse endianness:
// BigEndianReverse()
// ==================
bits(8*N) BigEndianReverse (bits(8*N) value, integer N)
assert N == 1 || N == 2 || N == 4 || N == 8;
bits(8*N) result;
case N of
when 1
result = value;
when 2
result = value;
result = value;
when 4
result = value;
result = value;
result = value;
result = value;
when 8
result = value;
result = value
result = value;
result = value;
result = value;
result = value;
result = value;
result = value;
return result;
B2-34 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B