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

Instruction Details
A8.6.165 SMC (previously SMI)
Secure Monitor Call is a system instruction. For details see SMC (previously SMI) on page B6-18.
A8.6.166 SMLABB, SMLABT, SMLATB, SMLATT
Signed Multiply Accumulate (halfwords) performs a signed multiply-accumulate operation. The multiply
acts on two signed 16-bit quantities, taken from either the bottom or the top half of their respective source
registers. The other halves of these source registers are ignored. The 32-bit product is added to a 32-bit
accumulate value and the result is written to the destination register.
If overflow occurs during the addition of the accumulate value, the instruction sets the Q flag in the APSR.
It is not possible for overflow to occur during the multiplication.
Encoding T1 ARMv6T2, ARMv7
SMLA ,,,
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 1 1 1 0 1 1 0 0 0 1 Rn Ra Rd 0 0 N M Rm
if Ra == ‘1111’ then SEE SMULBB, SMULBT, SMULTB, SMULTT;
d = UInt(Rd); n = UInt(Rn); m = UInt(Rm); a = UInt(Ra);
n_high = (N == ‘1’); m_high = (M == ‘1’);
if BadReg(d) || BadReg(n) || BadReg(m) || a == 13 then UNPREDICTABLE;
Encoding A1 ARMv5TE*, ARMv6*, ARMv7
SMLA ,,,
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
cond 0 0 0 1 0 0 0 0 Rd Ra Rm 1 M N 0 Rn
d = UInt(Rd); n = UInt(Rn); m = UInt(Rm); a = UInt(Ra);
n_high = (N == ‘1’); m_high = (M == ‘1’);
if d == 15 || n == 15 || m == 15 || a == 15 then UNPREDICTABLE;
A8-330 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B