Instruction Syntax and Addressing Modes

Table 4–5. MSP50P614/MSP50C614 Addressing Modes Summary

ADDRESSING

SYNTAX

OPERATION

Direct

name [dest,] [src,] *dma16 [*2] [, next A]

Second word operand (dma16) used directly as memory

 

name *dma16 [*2] [,src] [, next A]

address.

 

 

 

Long Relative

name [dest] [,src] ,*Rx+offset16 [, next A]

Selects one of 8 address registers as base value and adds

 

name *Rx+offset16 [,src] [, next A]

the value in the second word operand. Does not modify the

 

 

base address register.

 

 

Relative to R5 name [dest] [,src] ,*Rx+R5 [, next A]

Selects one of 8 address registers as base value and adds

(INDEX)

name *Rx+R5 [,src] [, next A]

the value in R5. Does not modify the base address register.

 

 

 

Indirect

name [dest] [, src] ,*Rx++R5 [, next A]

Selects one of 8 address registers to be used as the ad-

 

name [dest] [, src] ,*Rx [, next A]

dress, post modifications of increment, decrement, and +

 

name [dest] [, src] ,*Rx++ [, next A]

INDEX(R5) are possible.

 

name [dest] [, src] ,*Rx— [, next A]

 

 

name *Rx++R5 [, src] [, next A]

 

 

name *Rx [, src] [, next A]

 

 

name *Rx++ [, src] [, next A]

 

 

name *Rx––[, src] [, next A]

 

 

 

 

Short Relative name [dest] [, src] ,*R6+offset7 [, next A] name *R6+offset7 [, src] [, next A]

Selects PAGE(R6) register as the base address and adds a 7-bit positive address offset from operand field (b6–b0). This permits the relative addressing of 128 bytes or 64 words. Does not modify the PAGE address register. k is shown as constant.

Global Flag

name TFn, dma6

For use with flag instructions only. Adds lower 7 bits of

 

name dma6, TFn

instruction to a fixed address base reference of zero. 64

 

 

fixed flags are addressed by this mode beginning at ad-

 

 

dress 0000h.

 

 

 

Relative Flag

name TFn, *R6+offset6

For use with flag instructions only. Adds lower 7 bits of

 

name *R6+offset6, TFn

instruction(lsb set to zero) to a address base reference

 

 

stored in the PAGE register (R6). 64 flags relative to PAGE

 

 

may be addressed with this mode.

 

 

 

Table 4–6. Auto Increment and Auto Decrement Modes

Operation

Syntax

 

next A

 

 

 

 

 

No modification

 

0

 

0

 

 

 

 

 

Aufto decrement

––A

0

 

1

 

 

 

 

 

Auto increment

++A

1

 

0

 

 

 

 

 

String mode

 

1

 

1

 

 

 

 

 

Table 4–6 describes the accumulator pointer auto preincrement or predecrement syntax. Not all instructions can premodify accumulator pointers. The next A field is a two-bit field using bits 10 and 11 of only certain classes of instructions. Instructions with a [next A] have either a ––A or a ++A in the instruction. See Table 4–6.

Assembly Language Instructions

4-11

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Texas Instruments MSP50C6xx manual MSP50P614/MSP50C614 Addressing Modes Summary, Auto Increment and Auto Decrement Modes