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https://github.com/cirosantilli/linux-kernel-module-cheat.git
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a90271c6af
Split userland/arch/<arch>/c/ into inline_asm and intrinsics, and move programs that don't match either up.
35 lines
671 B
C
35 lines
671 B
C
/* Like inc.c but less good since we do more work ourselves.
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*
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* Just doing this to test out the "m" memory constraint.
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*
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* GCC 8.2.0 -O0 assembles ldr line to:
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*
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* ....
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* ldr r0, [fp, #-12]
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* ....
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*
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* and `-O3` assembles to:
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*
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* ....
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* ldr r0, [sp]
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* ....
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*
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* https://github.com/cirosantilli/linux-kernel-module-cheat#gcc-inline-assembly
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*/
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#include <assert.h>
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#include <inttypes.h>
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int main(void) {
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uint32_t my_local_var = 1;
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__asm__ (
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"ldr r0, %[my_local_var];"
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"add r0, r0, #1;"
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"str r0, %[my_local_var];"
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: [my_local_var] "+m" (my_local_var)
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:
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: "r0"
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);
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assert(my_local_var == 2);
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}
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