Freescale Semiconductor SC140 Last, or to last-1 Example, First execution set of the loop

Models: SC140

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DSP Core Instruction Set

Example:

 

lpmarkB;(set LA – 2)

_last

;(set LA – 1)

;(set LA)

In the case of a loop with two execution sets such as SA mark, the lpmarkB bit is set in the first execution set of the loop.

Example:

 

_start execution_set lpmarkB

j:

_last execution_set

;(this is a loop on two execution sets)

lpmarkA bit

 

 

In case of a loop with more than three execution sets, the lpmarkA bit is set in the prefix of the

 

execution set, which is at _last only if there were any SKIPLS, BREAK, CONT, CONTD to

 

_last, or to _last-1.

 

 

Example:

 

skipl _last

;(there is a skipl to _last in the program)

.

 

.

 

.

 

execution_set

 

execution_set

 

 

_last

execution_set lpmarkA

 

In the case of the loop having just one execution set, the lpmarkA bit is set in the prefix of the

 

first execution set of the loop.

EEE:

Data register expansion for DALU execution unit 0 (bit names: E1, E2, E3). This includes all

 

DALU instructions. For three-operand instructions (inst op1,op2,op3):

 

––1:

high data register is used for the op3 field (E3 is set)

 

–1–:

high data register is used for the op1 field (E2 is set)

 

1––:

high data register is used for the op2 field (E1 is set)

In case of two-operand MAC unit instructions, only E1 and E3 are used. In case of one-operand MAC unit instructions, only ––E3 is used.

In case of four-operand instructions with data registers defined as third and fourth operands, E1 and E3 used similarly to two-operand instructions.

Each of the E bits serves as a fourth register field encoding bit, effectively turning

FFF→ FFFF, etc. For example, the D0-7 registers are expanded to D0-15. Each E bit selects the low or high bank of registers for that field.

Fields representing multiple registers in DALU instructions could be scaled up independantly. For instance, the register pair encoding in the instruction MAX D0,D4 can be expanded to MAX D8,D4.

eee: The same as EEE, but for DALU execution unit 1.

BBB: The same as EEE, but for DALU execution unit 2.

bbb: The same as EEE, but for DALU execution unit 3.

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SC140 DSP Core Reference Manual

Page 324
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Freescale Semiconductor SC140 specifications Last, or to last-1 Example, First execution set of the loop