Texas Instruments MSP50C6xx User Manual
Page 115
Instruction Classification
4-29
Assembly Language Instructions
constants. Long constants (16 bits) and long string constants differ in that ref-
erences are made to constants in the second word of the two-word instruction
word. References made to a single 16-bit integer constant are immediate. That
is, the actual constant value follows the first word opcode in memory. For string
constants, the second word reference to the constants is immediate-indirect
which indicates that the second word is the address of the least significant
word of the string constant. This definition allows all long string constants to
be located in a table and permits the reference in the machine language listing
to be consistent with those of shorter constants.
Table 4–16. Class 2 Instruction Encoding
Bit
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Class 2a
1
0
1
0
C2a
An
imm8
Class 2b
1
1
1
0
0
next A
An
C2b
0
0
1
A~
~A
Table 4–17. Class 2a Instruction Description
C2a
Mnemonic
Description
0
0
0
ADDB An, imm8
Add an 8-bit positive constant to the accumulator and store the result in the
accumulator. ALU status is modified.
0
0
1
MOVB An, imm8
Load an 8-bit positive constant into accumulator. ALU status is modified.
0
1
0
SUBB An, imm8
Subtract 8-bit positive constant from accumulator and store result
accumulator. ALU status modified.
0
1
1
CMPB An, imm8
Modify ALU status with the result of 8-bit positive value subtracted from
accumulator. Original accumulator value not modified.
1
0
0
ORB An, imm8
Logical OR 8-bit positive constant with accumulator and store result to
accumulator. ALU status modified.
1
0
1
ANDB An, imm8
Logical AND 8-bit positive constant with accumulator. Store result to
accumulator. ALU status modified.
1
1
0
XORB An, imm8
Logical XOR 8-bit positive constant with accumulator. Store result to
accumulator. ALU status modified.
1
1
1
MOVB MR, imm8
Load 8-bit constant to Multiplier register (MR). Does not change UM mode in
status register but will zero fill the top 8 bits in MR register. No change in status.