diff options
Diffstat (limited to 'syscall.c')
| -rw-r--r-- | syscall.c | 24 |
1 files changed, 10 insertions, 14 deletions
@@ -15,18 +15,14 @@ #include "fd.h" #include "fcntl.h" -/* - * User code makes a system call with INT T_SYSCALL. - * System call number in %eax. - * Arguments on the stack, from the user call to the C - * library system call function. The saved user %esp points - * to a saved program counter, and then the first argument. - */ - -/* - * fetch 32 bits from a user-supplied pointer. - * returns 0 if addr was OK, -1 if illegal. - */ +// User code makes a system call with INT T_SYSCALL. +// System call number in %eax. +// Arguments on the stack, from the user call to the C +// library system call function. The saved user %esp points +// to a saved program counter, and then the first argument. + +// Fetch 32 bits from a user-supplied pointer. +// Returns 0 if addr was OK, -1 if illegal. int fetchint(struct proc *p, uint addr, int *ip) { @@ -58,8 +54,8 @@ fetcharg(int argno, void *ip) return fetchint(curproc[cpu()], esp + 4 + 4*argno, ip); } -// check that an entire string is valid in user space. -// returns the length, not including null, or -1. +// Check that an entire string is valid in user space. +// Returns the length, not including null, or -1. int checkstring(uint s) { |