Freescale Semiconductor SC140 specifications Prefix Selection Algorithm, Assembly Syntax Meaning

Models: SC140

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Instruction Grouping

 

Table 5-4. Conditional IFc Syntax

 

 

 

Assembly Syntax

 

Meaning

 

 

 

 

 

 

IFT inst [inst] IFF inst [inst]

 

Execution of subgroup1 if T==1

 

 

Execution of subgroup2 if T==0

 

 

 

IFT inst [inst]

 

Execution of the whole group if T==1

 

 

 

IFF inst [inst]

 

Execution of the whole group if T==0

 

 

 

IFT inst [inst] IFA inst [inst]

 

Execution of subgroup1 if T==1; always execute subgroup2

 

 

 

IFF inst [inst] IFA inst [inst]

 

Execution of subgroup1 if T==0; always execute subgroup2

 

 

 

5.2.4 Prefix Selection Algorithm

The grouping method (or encoding of prefix words) is not specified by the programmer. The assembler analyzes each execution set and attempts to group the instructions in a way that minimizes the number of instruction words. If possible, serial grouping is chosen. However, if extra grouping information is necessary, a one-word prefix is generated. A two-word prefix is generated only when high register banks are used in the execution set. The assembler encodes the execution set according to these principles, as shown in Figure 5-3.

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SC140 DSP Core Reference Manual

Page 190
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Freescale Semiconductor SC140 specifications Prefix Selection Algorithm, Assembly Syntax Meaning