pacman -S aarch64-linux-gnu-gccinstall bcm2835-1.52
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.52.tar.gz tar xzvf bcm2835-1.52.tar.gz cd bcm2835-1.52 ./configure CC=aarch64-linux-gnu-gcc CXX=aarch64-linux-gnu-g++ CPP=aarch64-linux-gnu-cpp --host=aarch64 make
func Inject(fptr,target interface{},before,after func([]reflect.Value)[]reflect.Value){
wrap := func(in []reflect.Value) []reflect.Value{
var b []reflect.Value
if before == nil {
b = in
} else {
b = before(in)
}
v := reflect.ValueOf(target)
r := v.Call(b)
if after == nil {
return r
} else {
return after(r)
}
}
fn := reflect.ValueOf(fptr).Elem()
v := reflect.MakeFunc(fn.Type(),wrap)
fn.Set(v)
}
使用实例：
func say(word string)string{
fmt.Println(word)
return word
}
func main(){
var impl func(string)string
m :=xx{}
Inject(&impl,say,
func(in []reflect.Value)[]reflect.Value{
fmt.Println("before")
return in
},
func(out []reflect.Value)[]reflect.Value{
fmt.Println("after")
vo := "new"
return []reflect.Value{reflect.ValueOf(vo)}
})
s:=impl("old")
}
运行结果:
before old after new
lsusb
Bus 001 Device 002: ID 0409:005a NEC Corp. HighSpeed Hub Bus 007 Device 003: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter Bus 008 Device 002: ID 1bcf:0002 Sunplus Innovation Technology Inc. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub找到usbserial设备的信息，这里是bus 007 Bus 007 Device 003: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter 然后装入usbserial模块, 根据结果修改vendor和product参数
sudo modprobe usbserial vendor=0x1a86 product=0x7523最后看看是否成功安装
lsmod | grep usbserial返回结果
usbserial 37161 1 ch341有上面一行信息意味安装成功 参考:http://forums.reprap.org/read.php?12,4546
a='a=%s; print( a %% repr(a))'; print( a % repr(a))go
/* Go quine */
package main
import "fmt"
func main() {
fmt.Printf("%s%c%s%c\n", q, 0x60, q, 0x60)
}
var q = `/* Go quine */
package main
import "fmt"
func main() {
fmt.Printf("%s%c%s%c\n", q, 0x60, q, 0x60)
}
var q = `
refer to
http://research.swtch.com/zip
#define LED2=0x04;
#define LED3=0x40;
void toggle_led(void){
static int idx=0;
if((++idx)&1)
__REG_B(GPKDAT) = LED2;
else
__REG_B(GPKDAT) = LED3;
}
优化编译后反汇编得到的代码是://omit the code of testing idx,
movne r2,#LED2
ldrne r3,=GPKDAT
strbne r2,[r3]
moveq r2,#LED3
ldreq r3,=GPKDAT
strbeq r2,[r3]
bx lr
我估计在编译的时候，这里的语句没办法优化因此会 3，4，6，7 行的多余出来。其实这4行用2行代码就可以了。
修改了C代码为#define LED2=0x04;
#define LED3=0x40;
void toggle(void){
static int idx=0;
unigned char temp;
if((++idx)&1)
temp = LED2;
else
temp = LED3;
__REG_B(GPKDAT) = temp;
}
代码编译后反编译：
//omit the code of testing idx
moveq r3,#LED2
movne r3,#LED3
ldr r2,=GPKDAT
strb r3,[r2]
估计是因为宏__REG_B中使用了volatile，因此对无法代码进行优化。