TMS320F datasheet(70/389 Pages) TI

70 / 389 page

Program-Address Generation

5-6

Pop operations are the reverse of push operations. A pop operation copies the

value at each level to the next higher level. Any pop after seven sequential

pops yields the value that was originally at the bottom of the stack because,

by then, the bottom value has been copied upward to all of the stack levels.

Figure 5–3 shows a pop operation.

Figure 5–3. A Pop Operation

Before Instruction

After Instruction

Accumulator

or memory

82h

or memory

45h

location

45h

16h

Stack

33h

42h

56h

37h

61h

5.1.3

Microstack (MSTACK)

The program-address generation logic uses the 16-bit-wide, 1-level-deep

MSTACK to store a return address before executing certain instructions.

These instructions use the program-address generation logic to provide a

second address in a 2-operand instruction. These instructions are: BLDD,

BLPD, MAC, MACD, TBLR, and TBLW. When repeated, these instructions

use the PC to increment the first operand address and can use the auxiliary

When these instructions are used, the return address (the address of the next

instruction to be fetched) is pushed onto the MSTACK. Upon completion of the

repeated instruction, the MSTACK value is popped back into the program-ad-

dress generation logic.

The MSTACK operations are not visible to you. Unlike the stack, the MSTACK

can be used only by the program-address generation logic; there are no

instructions that allow you to use the MSTACK for storage.

TMS320F Datasheet(PDF) 70 Page - Texas Instruments