We put each assembly function in its own section. So the sections for
64-bit signed and unsigned divide end up too far apart for b<cond>
(8-bit delta) or b (11-bit delta). Instead, use bl, which has no such
limit. This is a little less efficient in the case where numerator
and denominator are both positive, but equivalent if either or both is
negative, and is far outweighed by the cost of the unsigned divide
itself.
The other alternative would be to put both uldivmod and ldivmod in the
same section. However, we're often tight on code size on cortex-M0
parts, so that's less desirable.
BUG=chrome-os-partner:26126
BRANCH=minnie
TEST=add the following function
static int command_divtest(int argc, char **argv)
{
int64_t a, b, c;
char *e;
if (argc < 2)
return EC_ERROR_PARAM_COUNT;
a = strtoi(argv[1], &e, 0);
b = strtoi(argv[2], &e, 0);
c = a / b;
ccprintf("%d / %d = %d\n", (int)a, (int)b, (int)c);
return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(dt, command_divtest,
"a b",
"Divide test",
NULL);
and test with divides in all 4 quadrants (+/- 20 divided by +/- 5,
for example)
Change-Id: I2a5e49c4534044c2f509e325f8dd6bdf10b544c4
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/252243
Reviewed-by: Alec Berg <alecaberg@chromium.org>
These are needed for fixed-point math calculations.
Taken from the same public repo where we got the 32-bit divide
routines for Cortex-M0. With minor modifications to match changes
we've made so far for the existing divide routines (put each function
in its own section, delete dead code, etc.)
BUG=chrome-os-partner:36126
BRANCH=minnie
TEST=hack in a debug console command to allow arbitrary int64 divide, see that
it works as expected
Change-Id: I987dbca7c806c71bc38fa816971ac3a54c1641a5
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/244501
Reviewed-by: Alec Berg <alecaberg@chromium.org>
