a4971ede05
this is frequently desirable, but merely writing the obvious x % y formulation can lead to the 'undefined symbol __umoddi3' error. Linux provides some routines to do division of 64-bit quantities by 32-bit divisors; adopt this in rtapi, and provide a version written in the obvious way when in userspace.
35 lines
1.1 KiB
Text
35 lines
1.1 KiB
Text
.TH rtapi_div_u64 "3rtapi" "2006-10-12" "EMC Documentation" "RTAPI"
|
|
.SH NAME
|
|
|
|
rtapi_div_u64 \- unsigned division of a 64-bit number by a 32-bit number
|
|
|
|
.SH SYNTAX
|
|
.HP
|
|
__u64 rtapi_div_u64_rem(__u64 \fIdividend\fR, __u32 \fIdivisor\fR, __u32 *\fIremainder\fR)
|
|
.HP
|
|
__u64 rtapi_div_u64(__u64 \fIdividend\fR, __u32 \fIdivisor\fR)
|
|
|
|
.SH ARGUMENTS
|
|
.IP \fIdividend\fR
|
|
The value to be divided
|
|
.IP \fIdivisor\fR
|
|
The value to divide by
|
|
.IP \fIremainder\fR
|
|
Pointer to the location to store the remainder. This may not be a NULL
|
|
pointer. If the remainder is not desired, call \fBrtapi_div_u64\fR.
|
|
|
|
.SH DESCRIPTION
|
|
Perform integer division (and optionally compute the remainder) with a 64-bit dividend.
|
|
|
|
.SH RETURN VALUE
|
|
The result of integer division of \fIdividend / divisor\fR.
|
|
|
|
.SH NOTES
|
|
If the result of the division does not fit in a \fB__u32\fR, the result is undefined.
|
|
|
|
This function exists because in kernel space, the use of the division operator
|
|
on a 64-bit type can lead to an undefined symbol when the module is loaded.
|
|
|
|
.SH REALTIME CONSIDERATIONS
|
|
May be called from init/cleanup code and from within realtime tasks.
|
|
Available in userspace components.
|