mirror of
https://github.com/apache/nuttx.git
synced 2026-08-02 04:38:59 +00:00
61caf7cce9
in arm64 Let's see how the following code looks like in assembly
volatile cpu_set_t g_cpu_set;
cpu_set_t set_cpu_set_t_set(int cpu) {
g_cpu_set &= ~(1 << cpu);
return g_cpu_set;
}
when
typedef volatile uint32_t cpu_set_t;
Dump of assembler code for function set_cpu_set_t_set:
0x0000000040288570 <+0>: adrp x2, 0x403ce000 <g_irqvector+1160>
0x0000000040288574 <+4>: ldr w3, [x2, #2368]
0x0000000040288578 <+8>: mov w1, #0x1
0x000000004028857c <+12>: lsl w1, w1, w0
0x0000000040288580 <+16>: bic w1, w3, w1
0x0000000040288584 <+20>: str w1, [x2, #2368]
0x0000000040288588 <+24>: ldr w0, [x2, #2368]
0x000000004028858c <+28>: ret
when
typedef volatile uint8_t cpu_set_t;
Dump of assembler code for function set_cpu_set_t_set:
0x000000004028856c <+0>: adrp x2, 0x403ce000 <g_irqvector+1192>
0x0000000040288570 <+4>: ldrb w3, [x2, #2336]
0x0000000040288574 <+8>: mov w1, #0x1
0x0000000040288578 <+12>: and w3, w3, #0xff // At this time, there will be one more instruction
0x000000004028857c <+16>: lsl w1, w1, w0
0x0000000040288580 <+20>: bic w1, w3, w1
0x0000000040288584 <+24>: strb w1, [x2, #2336]
0x0000000040288588 <+28>: ldrb w0, [x2, #2336]
0x000000004028858c <+32>: ret
test:
We can use qemu for testing.
compiling
make distclean -j20; ./tools/configure.sh -l qemu-armv8a:nsh_smp ;make -j20
running
qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic -machine virt,virtualization=on,gic-version=3 -net none -chardev stdio,id=con,mux=on -serial chardev:con -mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
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|---|---|---|
| .. | ||
| boardctl.h | ||
| custom_file.h | ||
| endian.h | ||
| epoll.h | ||
| eventfd.h | ||
| file.h | ||
| ioctl.h | ||
| ipc.h | ||
| mman.h | ||
| mount.h | ||
| msg.h | ||
| param.h | ||
| poll.h | ||
| prctl.h | ||
| queue.h | ||
| random.h | ||
| resource.h | ||
| select.h | ||
| sendfile.h | ||
| shm.h | ||
| signalfd.h | ||
| socket.h | ||
| sockio.h | ||
| stat.h | ||
| statfs.h | ||
| statvfs.h | ||
| syscall.h | ||
| syscall_lookup.h | ||
| sysinfo.h | ||
| sysmacros.h | ||
| time.h | ||
| timerfd.h | ||
| times.h | ||
| tree.h | ||
| types.h | ||
| uio.h | ||
| un.h | ||
| utsname.h | ||
| vfs.h | ||
| video_controls.h | ||
| videoio.h | ||
| wait.h | ||