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rewrite MultiBootWaitCycles as naked function

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Before, when compiling MultiBootWaitCycles with O3 and MODERN=1, you
might have run into problems during optimizations when the compiler tried
to optimize the function, even if declared NOINLINE.

When rewriting this function as NAKED function, this no longer happens
as the optimizer will treat it as black box and compilation will resume.
This commit is contained in:
Michael Panzlaff 2020-10-02 12:12:31 +02:00
parent 5259898325
commit 187c96d6e5
1 changed files with 17 additions and 16 deletions
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33
src/multiboot.c
View file

@ -1,3 +1,4 @@
#include "global.h"
#include "gba/gba.h"
#include "multiboot.h"
@ -435,23 +436,23 @@ static int MultiBootHandShake(struct MultiBootParam *mp)
#undef must_data
}
static NOINLINE void MultiBootWaitCycles(u32 cycles)
NAKED
static void MultiBootWaitCycles(u32 cycles)
{
asm("mov r2, pc");
asm("lsr r2, #24");
asm("mov r1, #12");
asm("cmp r2, #0x02");
asm("beq MultiBootWaitCyclesLoop");
asm("mov r1, #13");
asm("cmp r2, #0x08");
asm("beq MultiBootWaitCyclesLoop");
asm("mov r1, #4");
asm("MultiBootWaitCyclesLoop:");
asm("sub r0, r1");
asm("bgt MultiBootWaitCyclesLoop");
asm_unified("\
mov r2, pc\n\
lsrs r2, 24\n\
movs r1, 12\n\
cmp r2, 2\n\
beq MultiBootWaitCyclesLoop\n\
movs r1, 13\n\
cmp r2, 8\n\
beq MultiBootWaitCyclesLoop\n\
movs r1, 4\n\
MultiBootWaitCyclesLoop:\n\
subs r0, r1\n\
bgt MultiBootWaitCyclesLoop\n\
bx lr\n");
}
static void MultiBootWaitSendDone(void)