Texas Instruments TMS320C80, Руководство пользователя

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Prototyping Code Using Linker Command Files
3-15 Prototyping ’C82 Code on the ’C80
Example 3–7.’C82 MP Linker Command File
/********************************************************
* c82mp.lnk – ’C82 MP linker command file
********************************************************/
–c
–x
–heap 0x2000
–stack 0x2000
–l mp_rts.lib
MEMORY
{
EXTMEM : o=0x02000000 l = 0x80000
MPPRAM : o=0x01010000 l = 0x1000
}
SECTIONS
{
.text : > EXTMEM
.ptext : > EXTMEM
.bss : > EXTMEM
.const : > EXTMEM
.switch : > EXTMEM
.sysmem : > EXTMEM
.stack : > EXTMEM
.cinit : > EXTMEM
.pcinit : > EXTMEM
}
3.4.6 Considerations when Using Linker Command Files
There are two basic considerations when prototyping ’C82 code
on a ’C80 using linker command files:
-
In some cases, code may run more quickly on the ’C80 than
on the ’C82. The probability of contention is lower in the ’C80
because each PP DRAM0, PP DRAM1, PP PRAM, and MP
PRAM is emulated by two RAMs in the ’C80.
-
In some cases, code may run more slowly on the ’C80 than
on the ’C82. Code that uses the local port to access DRAM1
could cause a 1-cycle stall during each access, since DRAM1
is not local to the ’C80 PPs.
3.4.6.1 Contention Differences in the ’C80 and ’C82
In the ’C82, contention exists between accesses to the first half
and last half of a RAM. In the ’C80, however, this contention does
not exist. A ’C80 PP can access the first and second halves of a
given RAM at the same time. On the other hand, a ’C82 PP can
only access either the first or second half of a given RAM in one
cycle. In the case of the ’C82, one access will be stalled until the
other access is complete.
This situation is one that you should avoid when you prototype
’C82 code on the ’C80; in the very least, take this into consider-
ation when estimating performance on the ’C82.