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set DIVISOR for each use of h/w divider

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This commit is contained in:
graham sanderson 2021-06-27 12:53:22 -05:00 committed by Luke Wren
parent 61b7cbdc54
commit 44feae4caf
2 changed files with 19 additions and 0 deletions
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2
src/rp2_common/pico_divider/divider.S
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@ -413,6 +413,7 @@ y64:
lsls r3,#16
orrs r3,r4
str r3,[r7,#SIO_DIV_UDIVIDEND_OFFSET] @ y1=(r0<<16)+(((ui32)y)>>16);
str r2,[r7,#SIO_DIV_UDIVISOR_OFFSET] @ must set divisor again, as we do not save/restore regs at all in IRQs if not dirty
wait_div 1
uxth r4,r0
ldr r3,[r7,#SIO_DIV_REMAINDER_OFFSET] @ r1=y1-q1*x; 0<=r1<x
@ -420,6 +421,7 @@ y64:
lsls r3,#16
orrs r3,r4
str r3,[r7,#SIO_DIV_UDIVIDEND_OFFSET] @ y1=(r0<<16)+(((ui32)y)>>16);
str r2,[r7,#SIO_DIV_UDIVISOR_OFFSET] @ must set divisor again, as we do not save/restore regs at all in IRQs if not dirty
wait_div 3
movs r3,#0
lsls r4,r5,#16 @ quotient=(q0<<32)+(q1<<16)+q2

17
test/pico_divider_test/pico_divider_nesting_test.c
View File

@ -158,6 +158,23 @@ void test_nesting() {
if (0xffffffffu != a * 11 + b) {
FAILED();
}
static uint64_t z64;
z64 -= 47;
uint64_t a64 = z64 / -13635;
uint64_t b64 = z64 % -13635;
if (z64 != a64 * -13635 + b64) {
FAILED();
}
// specifically check 64/32 divide
static uint64_t c64 = 0x13ffffffffull;
static uint32_t cd = 1;
a64 = c64 / cd;
b64 = c64 % cd;
if (c64 != a64 * cd + b64) {
FAILED();
}
cd++;
}
// these use the divider
for(uint i=0;i<=100;i+=20) {