Altera Nios II C2H Compiler Manuel d'utilisateur télécharger pdf (Page 104)

4–10 9.1 Altera Corporation

Nios II C2H Compiler User Guide November 2009

Performance

The performance section of the C2H build report details information

about each loop in the accelerated function. For each loop shown, the

report contains the following information:

■ File name and source line number

■ Loop latency

■ Cycles per loop iteration (CPLI)

■ Scheduling information per assignment

■ Scheduling information per state

In the following discussion of information shown in the performance

section, refer to Example 4–2.

Example 4–2. CRC32 (Ethernet CRC)

#pragma altera_accelerate connect_variable\

crc_calculation/data to onchipRAM1

#pragma altera_accelerate connect_variable\

crc_calculation/table to onchipRAM2

unsigned long crc_calculation

( unsigned char * __restrict__ data,

unsigned long * __restrict__ table,

unsigned long length)

{

unsigned long i, crc = 0xFFFFFFFF;

unsigned char lut_addr;

for (i = 0; i < length; i++)

{

lut_addr = (crc & 0xFF) ^ *data++;

crc = (crc >> 8) ^ table[lut_addr];

}

return (crc ^ 0xFFFFFFFF);

}

Source Line Number

The performance section of the build report shows a source line number

for each loop statement. The line number is determined by the beginning

of the loop, which is the source line containing the opening block

delimiter ({). If your coding style places the loop keyword (do, while, or

for) on a separate line from the delimiter, the report shows the line where

the delimiter appears.

1 2 ... 99 100 101 102 103 104 105 106 107 108 109 ... 137 138

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Altera Nios II C2H Compiler Manuel d'utilisateur Page 104