Rev. 1.50, 10/04, page 253 of 448
10.1.28 MAC.L (Multiply and Accumulate Long): Arithmetic Instruction
Format Operation Instruction Code Cycle T Bit
MAC.L @Rm+,@Rn+ Signed,
(Rn) × (Rm) + MAC → MAC
Rn + 4 → Rn, Rm + 4 → Rm
0000nnnnmmmm1111 5 —
Description: This instruction performs signed multiplication of the 32-bit operands whose
addresses are the contents of general registers Rm and Rn, adds the 64-bit result to the MAC
register contents, and stores the result in the MAC register. Operands Rm and Rn are each
incremented by 4 each time they are read.
If the S bit is 0, the 64-bit result is stored in the linked MACH and MACL registers.
If the S bit is 1, the addition to the MAC register contents is a saturation operation at the 48th bit
from the LSB. In a saturation operation, only the lower 48 bits of the MAC register are valid, and
the result range is limited to H'FFFF800000000000 (minimum value) to H'00007FFFFFFFFFFF
(maximum value).
Notes: None
Operation:
MACL(long m, long n) /* MAC.L @Rm+,@Rn+ */
{
unsigned long RnL,RnH,RmL,RmH,Res0,Res1,Res2;
unsigned long temp0,temp1,temp2,temp3;
long tempm,tempn,fnLmL;
tempn = (long)Read_Long(R[n]);
R[n] += 4;
tempm = (long)Read_Long(R[m]);
R[m] += 4;
if ((long)(tempn^tempm)<0) fnLmL = -1;
else fnLmL = 0;
if (tempn<0) tempn = 0-tempn;
if (tempm<0) tempm = 0-tempm;
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