include math.h時 需要在編譯的時候加上 -lm參數(for linker)
ex: gcc ex.c -lm -o ex
include stdio.h 需要加上-lc 參數
一般不加的原因, 是因為-lc是default參數
include math.h時 需要在編譯的時候加上 -lm參數(for linker)
ex: gcc ex.c -lm -o ex
include stdio.h 需要加上-lc 參數
一般不加的原因, 是因為-lc是default參數
#!/usr/bin/perl
$foo = 123;
$hexval = sprintf(“%x", $foo);
$decval = hex($hexval);
print “\n$foo in hex is $hexval and in dec is $decval\n";
gcode = gray code
assign g2b[3] = gcode[3];
assign g2b[2] = g2b[3] & gcode[2];
assign g2b[1] = g2b[2] & gcode[1];
assign g2b[0] = g2b[1] & gcode[0];
assign b2g[3] = bcode[3];
assign b2g[2] = bcode[3] & bcode[2];
assign b2g[1] = bcode[2] & bcode[1];
assign b2g[0] = bcode[1] & bcode[0];
unsigned int k,len;
volatile unsigned int *tmp_s;
tmp_s = (volatile unsigned int *) 0x1FFCF000;
for(k=0;k<40;k++)
{
*((volatile unsigned int *)(tmp_s))=k;
tmp_s = tmp_s + 1;
}
上面寫法由armcc compile之後每次addr是跳4.
若改成
unsigned int k,len,tmp_s;
tmp_s = 0x1FFCF000;
for(k=0;k<40;k++)
{
*((volatile unsigned int *)(tmp_s))=k;
tmp_s = tmp_s + 1;
}
則每次addr跳1.
與宣告變數型態有關.