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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`’, ‘`bf542m`’, ‘`bf544m`’, ‘`bf547m`’, ‘`bf548m`’, ‘`bf549m`’, ‘`bf561`’, ‘`bf592`’. 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 lies 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 run time. 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.

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