WebOct 25, 2024 · In C++, we can create a pointer to a pointer that in turn may point to data or another pointer. The syntax simply requires the unary operator (*) for each level of indirection while declaring the pointer. char a; char *b; char ** c; a = ’g’; b = &a; c = &b; Here b points to a char that stores ‘g’ and c points to the pointer b. Void Pointers WebTo input a byte (8 bits) from a port, call inb (port), it returns the byte it got. To output a byte, call outb (value, port) (please note the order of the parameters). To input a word (16 bits) from ports x and x+1 (one byte from each to form the word, using the assembler instruction inw ), call inw (x).

inb: access I/O ports - Linux Man Pages (1) - SysTutorials

WebFeb 17, 2016 · Feb 16, 2016 at 23:38. 1. Note that you don't even need the &0xff. Ideally gcc would make code like outb %al, $40 / shr $16, %eax / outb %al, $42. Your code at best gets gcc to shift in another register and mov %somewhere, %al before every out. (Maybe taking advantage of mov %dh, %al and similar). At worst, copies and masks after every shift. WebJan 22, 2012 · The specific C code that you present relates to the 8259A Programmable Interrupt Controller (PIC). You can read about the PIC here and here. If that doesn't provide enough details to understand the commands and the bit masks, you could always refer to … sedge hollow

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Web15 hours ago · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ... WebSep 5, 2024 · In C, like normal data pointers (int *, char *, etc), we can have pointers to functions. Following is a simple example that shows declaration and function call using function pointer. #include void fun (int a) { printf("Value of a is %d\n", a); } int main () { void (*fun_ptr) (int) = &fun; void (*fun_ptr) (int); fun_ptr = &fun; WebAbout Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ... sedgehill sixth form