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

Application Level Programmers’ Model
(result, -) = LSL_C(x, shift);
return result;
// LSR_C()
// =======
(bits(N), bit) LSR_C(bits(N) x, integer shift)
assert shift > 0;
extended_x = ZeroExtend(x, shift+N);
result = extended_x;
carry_out = extended_x;
return (result, carry_out);
// LSR()
// =====
bits(N) LSR(bits(N) x, integer shift)
assert shift >= 0;
if shift == 0 then
result = x;
else
(result, -) = LSR_C(x, shift);
return result;
// ASR_C()
// =======
(bits(N), bit) ASR_C(bits(N) x, integer shift)
assert shift > 0;
extended_x = SignExtend(x, shift+N);
result = extended_x;
carry_out = extended_x;
return (result, carry_out);
// ASR()
// =====
bits(N) ASR(bits(N) x, integer shift)
assert shift >= 0;
if shift == 0 then
result = x;
else
(result, -) = ASR_C(x, shift);
return result;
// ROR_C()
// =======
(bits(N), bit) ROR_C(bits(N) x, integer shift)
assert shift != 0;
m = shift MOD N;
result = LSR(x,m) OR LSL(x,N-m);
carry_out = result;
return (result, carry_out);
A2-6 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B