Bit Field Manipulation Instructions; Loop Instructions; Move Instructions - Motorola DSP56156 Manual

1.7.1.3

Bit Field Manipulation Instructions

This group tests the state of any set of bits within a byte in a memory location or a register
and then sets, clears, or inverts bits in this byte. Bit fields which can be tested include the
upper byte and the lower byte in a 16 bit value. The carry bit of the condition code register
will contain the result of the bit test for each instruction. These instructions are read-mod-
ify-write and require two instruction cycles. Parallel data moves are not allowed with any
of these instructions. The following are the bit field manipulation instructions.
BFTSTL Bit Field Test Low
BFTSTH Bit Field Test High
BFCLR Bit Field Test and Clear
BFSET Bit Field Test and Set
BFCHG Bit Field Test and Change
1.7.1.4

Loop Instructions

The loop instructions control hardware looping by initiating a program loop and setting up
looping parameters, or by "cleaning" up the system stack when terminating a loop. Initial-
ization includes saving registers used by a program loop (LA and LC) on the system stack
so that program loops can be nested. The address of the first instruction in a program loop
is also saved to allow no-overhead looping. The end address of the DO loop is specified
as PC relative. Parallel data moves are not allowed with any of these instructions. The fol-
lowing are the loop instructions.
DO Start Hardware Loop
DO FOREVER Hardware Loop for ever
ENDDO Disable Current Loop and Unstack Parameters
BRKcc Conditional Exit from Hardware Loop
1.7.1.5

Move Instructions

The move instructions perform data movement over the XDB and over the GDB. Move
instructions do not affect the condition code register except the limit bit, L, if limiting is per-
formed or the Sticky Bit, S, when reading a Data ALU accumulator register. AGU instruc-
tions are also included among the following move instructions. These instructions do not
allow optional data transfers.
LEA Load Effective Address
MOVE Move Data with or without Register Transfer – TFR(3)
MOVE(C) Move Control Register
MOVE(I) Move Immediate Short
MOVE(M) Move Program Memory
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INSTRUCTION SET SUMMARY
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