1 # Target definition: architecture, optimisations, etc...
8 # Pre-declare target optimisation variables
9 config ARCH_SUPPORTS_BOTH_MMU
10 config ARCH_SUPPORTS_BOTH_ENDIAN
11 config ARCH_SUPPORTS_32
12 config ARCH_SUPPORTS_64
13 config ARCH_SUPPORT_ARCH
14 config ARCH_SUPPORT_ABI
15 config ARCH_SUPPORT_CPU
16 config ARCH_SUPPORT_TUNE
17 config ARCH_SUPPORT_FPU
18 config ARCH_SUPPORT_SOFTFP
20 config ARCH_DEFAULT_HAS_MMU
21 config ARCH_DEFAULT_BE
22 config ARCH_DEFAULT_LE
23 config ARCH_DEFAULT_32
24 config ARCH_DEFAULT_64
41 source "config.gen/arch.in"
43 #--------------------------------------
44 comment "Generic target options"
46 config ARCH_SUPPORTS_BOTH_MMU
49 config ARCH_DEFAULT_HAS_MMU
54 prompt "Use the MMU" if ARCH_SUPPORTS_BOTH_MMU
55 default y if ARCH_DEFAULT_HAS_MMU
57 If your architecture has an MMU and you want to use it,
60 OTOH, if you don't want to use the MMU, or your arch
61 lacks an MMU, say 'N' here.
63 Note that some architectures (eg. ARM) has variants that
64 lacks an MMU (eg. ARM Cortex-M3), while other variants
65 have one (eg. ARM Cortex-A8).
67 #--------------------------------------
68 config ARCH_SUPPORTS_BOTH_ENDIAN
71 config ARCH_DEFAULT_BE
74 config ARCH_DEFAULT_LE
80 depends on ARCH_SUPPORTS_BOTH_ENDIAN
81 default ARCH_BE if ARCH_DEFAULT_BE
82 default ARCH_LE if ARCH_DEFAULT_LE
90 prompt "Little endian"
94 #--------------------------------------
95 config ARCH_SUPPORTS_32
98 config ARCH_SUPPORTS_64
101 config ARCH_DEFAULT_32
104 config ARCH_DEFAULT_64
109 default "32" if ARCH_32
110 default "64" if ARCH_64
115 default ARCH_32 if ARCH_DEFAULT_32
116 default ARCH_64 if ARCH_DEFAULT_64
121 depends on ARCH_SUPPORTS_32
126 depends on ARCH_SUPPORTS_64
130 #--------------------------------------
131 comment "Target optimisations"
133 config ARCH_SUPPORT_ARCH
136 config ARCH_SUPPORT_ABI
139 config ARCH_SUPPORT_CPU
142 config ARCH_SUPPORT_TUNE
145 config ARCH_SUPPORT_FPU
148 config ARCH_SUPPORT_SOFTFP
153 prompt "Architecture level"
154 depends on ARCH_SUPPORT_ARCH
157 GCC uses this name to determine what kind of instructions it can emit
158 when generating assembly code. This option can be used in conjunction
159 with or instead of the ARCH_CPU option (above), or a (command-line)
162 This is the configuration flag --with-arch=XXXX, and the runtime flag
165 Pick a value from the gcc manual for your choosen gcc version and your
168 Leave blank if you don't know, or if your target architecture does not
173 prompt "Generate code for the specific ABI"
174 depends on ARCH_SUPPORT_ABI
177 Generate code for the given ABI.
179 This is the configuration flag --with-abi=XXXX, and the runtime flag
182 Pick a value from the gcc manual for your choosen gcc version and your
185 Leave blank if you don't know, or if your target architecture does not
190 prompt "Emit assembly for CPU"
191 depends on ARCH_SUPPORT_CPU
194 This specifies the name of the target processor. GCC uses this name
195 to determine what kind of instructions it can emit when generating
198 This is the configuration flag --with-cpu=XXXX, and the runtime flag
201 Pick a value from the gcc manual for your choosen gcc version and your
204 Leave blank if you don't know, or if your target architecture does not
209 prompt "Tune for CPU"
210 depends on ARCH_SUPPORT_TUNE
213 This option is very similar to the ARCH_CPU option (above), except
214 that instead of specifying the actual target processor type, and hence
215 restricting which instructions can be used, it specifies that GCC should
216 tune the performance of the code as if the target were of the type
217 specified in this option, but still choosing the instructions that it
218 will generate based on the cpu specified by the ARCH_CPU option
219 (above), or a (command-line) -mcpu= option.
221 This is the configuration flag --with-tune=XXXX, and the runtime flag
224 Pick a value from the gcc manual for your choosen gcc version and your
227 Leave blank if you don't know, or if your target architecture does not
232 prompt "Use specific FPU"
233 depends on ARCH_SUPPORT_FPU
236 On some targets (eg. ARM), you can specify the kind of FPU to emit
239 This is the configuration flag --with-fpu=XXX, and the runtime flag
242 See below wether to actually emit FP opcodes, or to emulate them.
244 Pick a value from the gcc manual for your choosen gcc version and your
247 Leave blank if you don't know, or if your target architecture does not
252 prompt "Floating point:"
256 prompt "hardware (FPU)"
258 Emit hardware floating point opcodes.
260 If you've got a processor with a FPU, then you want that.
261 If your hardware has no FPU, you still can use HW floating point, but
262 need to compile support for FPU emulation in your kernel. Needless to
263 say that emulating the FPU is /slooowwwww/...
265 One situation you'd want HW floating point without a FPU is if you get
266 binary blobs from different vendors that are compiling this way and
267 can't (don't wan't to) change.
273 Do not emit any hardware floating point opcode.
275 If your processor has no FPU, then you most probably want this, as it
276 is faster than emulating the FPU in the kernel.
278 config ARCH_FLOAT_SOFTFP
281 depends on ARCH_SUPPORT_SOFTFP
283 Emit hardware floating point opcodes but use the software
284 floating point calling convention.
286 Architectures such as ARM use different registers for passing
287 floating point values depending on if they're in software mode
288 or hardware mode. softfp emits FPU instructions but uses the
289 software FP calling convention allowing softfp code to
290 interoperate with legacy software only code.
292 If in doubt, use 'software' or 'hardware' mode instead.
298 prompt "Target CFLAGS"
301 Used to add specific options when compiling libraries of the toolchain,
302 that will run on the target (eg. libc.so).
304 Note that the options above for ARCH, ABI, CPU, TUNE and FPU will be
305 automatically used. You don't need to specify them here.
307 Leave blank if you don't know better.
309 config TARGET_LDFLAGS
311 prompt "Target LDFLAGS"
314 Used to add specific options when linking libraries of the toolchain,
315 that will run on your target.
317 Leave blank if you don't know better.
321 default "hard" if ARCH_FLOAT_HW
322 default "soft" if ARCH_FLOAT_SW
323 default "softfp" if ARCH_FLOAT_SOFTFP
325 source "config.gen/arch.in.2"