blob: 440ca97a35dcdc840aa493280345042dcbf7a215 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
#ifndef __INC_DELAY_H
#define __INC_DELAY_H
////////////////////////////////////////////////////////////////////////////////////////////
//
// Clock cycle counted delay loop
//
////////////////////////////////////////////////////////////////////////////////////////////
#if defined(__arm__)
# define NOP __asm__ __volatile__ ("nop\n");
#else
# define NOP __asm__ __volatile__ ("cp r0,r0\n");
#endif
// predeclaration to not upset the compiler
template<int CYCLES> inline void delaycycles();
// TODO: ARM version of _delaycycles_
// worker template - this will nop for LOOP * 3 + PAD cycles total
template<int LOOP, int PAD> inline void _delaycycles_AVR() {
delaycycles<PAD>();
// the loop below is 3 cycles * LOOP. the LDI is one cycle,
// the DEC is 1 cycle, the BRNE is 2 cycles if looping back and
// 1 if not (the LDI balances out the BRNE being 1 cycle on exit)
__asm__ __volatile__ (
" LDI R16, %0\n"
"L_%=: DEC R16\n"
" BRNE L_%=\n"
: /* no outputs */
: "M" (LOOP)
: "r16"
);
}
// usable definition
#if !defined(__MK20DX128__)
template<int CYCLES> __attribute__((always_inline)) inline void delaycycles() {
_delaycycles_AVR<CYCLES / 3, CYCLES % 3>();
}
#else
template<int CYCLES> __attribute__((always_inline)) inline void delaycycles() {
NOP; delaycycles<CYCLES-1>();
}
#endif
// pre-instantiations for values small enough to not need the loop, as well as sanity holders
// for some negative values.
template<> __attribute__((always_inline)) inline void delaycycles<-3>() {}
template<> __attribute__((always_inline)) inline void delaycycles<-2>() {}
template<> __attribute__((always_inline)) inline void delaycycles<-1>() {}
template<> __attribute__((always_inline)) inline void delaycycles<0>() {}
template<> __attribute__((always_inline)) inline void delaycycles<1>() {NOP;}
template<> __attribute__((always_inline)) inline void delaycycles<2>() {NOP;NOP;}
template<> __attribute__((always_inline)) inline void delaycycles<3>() {NOP;NOP;NOP;}
template<> __attribute__((always_inline)) inline void delaycycles<4>() {NOP;NOP;NOP;NOP;}
template<> __attribute__((always_inline)) inline void delaycycles<5>() {NOP;NOP;NOP;NOP;NOP;}
#endif
|
