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3.17.4 Blackfin Options

-mcpu=cpu[-sirevision]
Specifies the name of the target Blackfin processor. Currently, cpu can be one of bf512, bf514, bf516, bf518, bf522, bf523, bf524, bf525, bf526, bf527, bf531, bf532, bf533, bf534, bf536, bf537, bf538, bf539, bf542, bf544, bf547, bf548, bf549, bf561. The optional sirevision specifies the silicon revision of the target Blackfin processor. Any workarounds available for the targeted silicon revision will be enabled. If sirevision is none, no workarounds are enabled. If sirevision is any, all workarounds for the targeted processor will be enabled. The __SILICON_REVISION__ macro is defined to two hexadecimal digits representing the major and minor numbers in the silicon revision. If sirevision is none, the __SILICON_REVISION__ is not defined. If sirevision is any, the __SILICON_REVISION__ is defined to be 0xffff. If this optional sirevision is not used, GCC assumes the latest known silicon revision of the targeted Blackfin processor.

Support for bf561 is incomplete. For bf561, Only the processor macro is defined. Without this option, bf532 is used as the processor by default. The corresponding predefined processor macros for cpu is to be defined. And for bfin-elf toolchain, this causes the hardware BSP provided by libgloss to be linked in if -msim is not given.

-msim
Specifies that the program will be run on the simulator. This causes the simulator BSP provided by libgloss to be linked in. This option has effect only for bfin-elf toolchain. Certain other options, such as -mid-shared-library and -mfdpic, imply -msim.
-momit-leaf-frame-pointer
Don't keep the frame pointer in a register for leaf functions. This avoids the instructions to save, set up and restore frame pointers and makes an extra register available in leaf functions. The option -fomit-frame-pointer removes the frame pointer for all functions which might make debugging harder.
-mspecld-anomaly
When enabled, the compiler will ensure that the generated code does not contain speculative loads after jump instructions. If this option is used, __WORKAROUND_SPECULATIVE_LOADS is defined.
-mno-specld-anomaly
Don't generate extra code to prevent speculative loads from occurring.
-mcsync-anomaly
When enabled, the compiler will ensure that the generated code does not contain CSYNC or SSYNC instructions too soon after conditional branches. If this option is used, __WORKAROUND_SPECULATIVE_SYNCS is defined.
-mno-csync-anomaly
Don't generate extra code to prevent CSYNC or SSYNC instructions from occurring too soon after a conditional branch.
-mlow-64k
When enabled, the compiler is free to take advantage of the knowledge that the entire program fits into the low 64k of memory.
-mno-low-64k
Assume that the program is arbitrarily large. This is the default.
-mstack-check-l1
Do stack checking using information placed into L1 scratchpad memory by the uClinux kernel.
-mid-shared-library
Generate code that supports shared libraries via the library ID method. This allows for execute in place and shared libraries in an environment without virtual memory management. This option implies -fPIC. With a bfin-elf target, this option implies -msim.
-mno-id-shared-library
Generate code that doesn't assume ID based shared libraries are being used. This is the default.
-mleaf-id-shared-library
Generate code that supports shared libraries via the library ID method, but assumes that this library or executable won't link against any other ID shared libraries. That allows the compiler to use faster code for jumps and calls.
-mno-leaf-id-shared-library
Do not assume that the code being compiled won't link against any ID shared libraries. Slower code will be generated for jump and call insns.
-mshared-library-id=n
Specified the identification number of the ID based shared library being compiled. Specifying a value of 0 will generate more compact code, specifying other values will force the allocation of that number to the current library but is no more space or time efficient than omitting this option.
-msep-data
Generate code that allows the data segment to be located in a different area of memory from the text segment. This allows for execute in place in an environment without virtual memory management by eliminating relocations against the text section.
-mno-sep-data
Generate code that assumes that the data segment follows the text segment. This is the default.
-mlong-calls
-mno-long-calls
Tells the compiler to perform function calls by first loading the address of the function into a register and then performing a subroutine call on this register. This switch is needed if the target function will lie outside of the 24 bit addressing range of the offset based version of subroutine call instruction.

This feature is not enabled by default. Specifying -mno-long-calls will restore the default behavior. Note these switches have no effect on how the compiler generates code to handle function calls via function pointers.

-mfast-fp
Link with the fast floating-point library. This library relaxes some of the IEEE floating-point standard's rules for checking inputs against Not-a-Number (NAN), in the interest of performance.
-minline-plt
Enable inlining of PLT entries in function calls to functions that are not known to bind locally. It has no effect without -mfdpic.
-mmulticore
Build standalone application for multicore Blackfin processor. Proper start files and link scripts will be used to support multicore. This option defines __BFIN_MULTICORE. It can only be used with -mcpu=bf561[-sirevision]. It can be used with -mcorea or -mcoreb. If it's used without -mcorea or -mcoreb, single application/dual core programming model is used. In this model, the main function of Core B should be named as coreb_main. If it's used with -mcorea or -mcoreb, one application per core programming model is used. If this option is not used, single core application programming model is used.
-mcorea
Build standalone application for Core A of BF561 when using one application per core programming model. Proper start files and link scripts will be used to support Core A. This option defines __BFIN_COREA. It must be used with -mmulticore.
-mcoreb
Build standalone application for Core B of BF561 when using one application per core programming model. Proper start files and link scripts will be used to support Core B. This option defines __BFIN_COREB. When this option is used, coreb_main should be used instead of main. It must be used with -mmulticore.
-msdram
Build standalone application for SDRAM. Proper start files and link scripts will be used to put the application into SDRAM. Loader should initialize SDRAM before loading the application into SDRAM. This option defines __BFIN_SDRAM.
-micplb
Assume that ICPLBs are enabled at runtime. This has an effect on certain anomaly workarounds. For Linux targets, the default is to assume ICPLBs are enabled; for standalone applications the default is off.