From 4206a3cd77d6378a98790552290f990d10c33532 Mon Sep 17 00:00:00 2001
From: Cristian Maglie <c.maglie@arduino.cc>
Date: Thu, 11 Sep 2014 18:57:00 +0200
Subject: [PATCH] Simplified formula for SPI divisor calculation
---
libraries/SPI/SPI.h | 276 ++------------------------------------------
1 file changed, 7 insertions(+), 269 deletions(-)
diff --git a/libraries/SPI/SPI.h b/libraries/SPI/SPI.h
index 333a2f4e..34d0e1ba 100644
--- a/libraries/SPI/SPI.h
+++ b/libraries/SPI/SPI.h
@@ -27,281 +27,19 @@ class SPISettings {
init_MightInline(clock, bitOrder, dataMode);
}
}
- SPISettings() {
- init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0);
- }
+ SPISettings() { init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0); }
private:
void init_MightInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode) {
init_AlwaysInline(clock, bitOrder, dataMode);
}
- void init_AlwaysInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode)
- __attribute__((__always_inline__)) {
+ void init_AlwaysInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode) __attribute__((__always_inline__)) {
uint8_t div;
- if (__builtin_constant_p(clock)) {
- if (clock >= F_CPU / 2) div = 2;
- else if (clock >= F_CPU / 3) div = 3;
- else if (clock >= F_CPU / 4) div = 4;
- else if (clock >= F_CPU / 5) div = 5;
- else if (clock >= F_CPU / 6) div = 6;
- else if (clock >= F_CPU / 7) div = 7;
- else if (clock >= F_CPU / 8) div = 8;
- else if (clock >= F_CPU / 9) div = 9;
- else if (clock >= F_CPU / 10) div = 10;
- else if (clock >= F_CPU / 11) div = 11;
- else if (clock >= F_CPU / 12) div = 12;
- else if (clock >= F_CPU / 13) div = 13;
- else if (clock >= F_CPU / 14) div = 14;
- else if (clock >= F_CPU / 15) div = 15;
- else if (clock >= F_CPU / 16) div = 16;
- else if (clock >= F_CPU / 17) div = 17;
- else if (clock >= F_CPU / 18) div = 18;
- else if (clock >= F_CPU / 19) div = 19;
- else if (clock >= F_CPU / 20) div = 20;
- else if (clock >= F_CPU / 21) div = 21;
- else if (clock >= F_CPU / 22) div = 22;
- else if (clock >= F_CPU / 23) div = 23;
- else if (clock >= F_CPU / 24) div = 24;
- else if (clock >= F_CPU / 25) div = 25;
- else if (clock >= F_CPU / 26) div = 26;
- else if (clock >= F_CPU / 27) div = 27;
- else if (clock >= F_CPU / 28) div = 28;
- else if (clock >= F_CPU / 29) div = 29;
- else if (clock >= F_CPU / 30) div = 30;
- else if (clock >= F_CPU / 31) div = 31;
- else if (clock >= F_CPU / 32) div = 32;
- else if (clock >= F_CPU / 33) div = 33;
- else if (clock >= F_CPU / 34) div = 34;
- else if (clock >= F_CPU / 35) div = 35;
- else if (clock >= F_CPU / 36) div = 36;
- else if (clock >= F_CPU / 37) div = 37;
- else if (clock >= F_CPU / 38) div = 38;
- else if (clock >= F_CPU / 39) div = 39;
- else if (clock >= F_CPU / 40) div = 40;
- else if (clock >= F_CPU / 41) div = 41;
- else if (clock >= F_CPU / 42) div = 42;
- else if (clock >= F_CPU / 43) div = 43;
- else if (clock >= F_CPU / 44) div = 44;
- else if (clock >= F_CPU / 45) div = 45;
- else if (clock >= F_CPU / 46) div = 46;
- else if (clock >= F_CPU / 47) div = 47;
- else if (clock >= F_CPU / 48) div = 48;
- else if (clock >= F_CPU / 49) div = 49;
- else if (clock >= F_CPU / 50) div = 50;
- else if (clock >= F_CPU / 51) div = 51;
- else if (clock >= F_CPU / 52) div = 52;
- else if (clock >= F_CPU / 53) div = 53;
- else if (clock >= F_CPU / 54) div = 54;
- else if (clock >= F_CPU / 55) div = 55;
- else if (clock >= F_CPU / 56) div = 56;
- else if (clock >= F_CPU / 57) div = 57;
- else if (clock >= F_CPU / 58) div = 58;
- else if (clock >= F_CPU / 59) div = 59;
- else if (clock >= F_CPU / 60) div = 60;
- else if (clock >= F_CPU / 61) div = 61;
- else if (clock >= F_CPU / 62) div = 62;
- else if (clock >= F_CPU / 63) div = 63;
- else if (clock >= F_CPU / 64) div = 64;
- else if (clock >= F_CPU / 65) div = 65;
- else if (clock >= F_CPU / 66) div = 66;
- else if (clock >= F_CPU / 67) div = 67;
- else if (clock >= F_CPU / 68) div = 68;
- else if (clock >= F_CPU / 69) div = 69;
- else if (clock >= F_CPU / 70) div = 70;
- else if (clock >= F_CPU / 71) div = 71;
- else if (clock >= F_CPU / 72) div = 72;
- else if (clock >= F_CPU / 73) div = 73;
- else if (clock >= F_CPU / 74) div = 74;
- else if (clock >= F_CPU / 75) div = 75;
- else if (clock >= F_CPU / 76) div = 76;
- else if (clock >= F_CPU / 77) div = 77;
- else if (clock >= F_CPU / 78) div = 78;
- else if (clock >= F_CPU / 79) div = 79;
- else if (clock >= F_CPU / 80) div = 80;
- else if (clock >= F_CPU / 81) div = 81;
- else if (clock >= F_CPU / 82) div = 82;
- else if (clock >= F_CPU / 83) div = 83;
- else if (clock >= F_CPU / 84) div = 84;
- else if (clock >= F_CPU / 85) div = 85;
- else if (clock >= F_CPU / 86) div = 86;
- else if (clock >= F_CPU / 87) div = 87;
- else if (clock >= F_CPU / 88) div = 88;
- else if (clock >= F_CPU / 89) div = 89;
- else if (clock >= F_CPU / 90) div = 90;
- else if (clock >= F_CPU / 91) div = 91;
- else if (clock >= F_CPU / 92) div = 92;
- else if (clock >= F_CPU / 93) div = 93;
- else if (clock >= F_CPU / 94) div = 94;
- else if (clock >= F_CPU / 95) div = 95;
- else if (clock >= F_CPU / 96) div = 96;
- else if (clock >= F_CPU / 97) div = 97;
- else if (clock >= F_CPU / 98) div = 98;
- else if (clock >= F_CPU / 99) div = 99;
- else if (clock >= F_CPU / 100) div = 100;
- else if (clock >= F_CPU / 101) div = 101;
- else if (clock >= F_CPU / 102) div = 102;
- else if (clock >= F_CPU / 103) div = 103;
- else if (clock >= F_CPU / 104) div = 104;
- else if (clock >= F_CPU / 105) div = 105;
- else if (clock >= F_CPU / 106) div = 106;
- else if (clock >= F_CPU / 107) div = 107;
- else if (clock >= F_CPU / 108) div = 108;
- else if (clock >= F_CPU / 109) div = 109;
- else if (clock >= F_CPU / 110) div = 110;
- else if (clock >= F_CPU / 111) div = 111;
- else if (clock >= F_CPU / 112) div = 112;
- else if (clock >= F_CPU / 113) div = 113;
- else if (clock >= F_CPU / 114) div = 114;
- else if (clock >= F_CPU / 115) div = 115;
- else if (clock >= F_CPU / 116) div = 116;
- else if (clock >= F_CPU / 117) div = 117;
- else if (clock >= F_CPU / 118) div = 118;
- else if (clock >= F_CPU / 119) div = 119;
- else if (clock >= F_CPU / 120) div = 120;
- else if (clock >= F_CPU / 121) div = 121;
- else if (clock >= F_CPU / 122) div = 122;
- else if (clock >= F_CPU / 123) div = 123;
- else if (clock >= F_CPU / 124) div = 124;
- else if (clock >= F_CPU / 125) div = 125;
- else if (clock >= F_CPU / 126) div = 126;
- else if (clock >= F_CPU / 127) div = 127;
- else if (clock >= F_CPU / 128) div = 128;
- else if (clock >= F_CPU / 129) div = 129;
- else if (clock >= F_CPU / 130) div = 130;
- else if (clock >= F_CPU / 131) div = 131;
- else if (clock >= F_CPU / 132) div = 132;
- else if (clock >= F_CPU / 133) div = 133;
- else if (clock >= F_CPU / 134) div = 134;
- else if (clock >= F_CPU / 135) div = 135;
- else if (clock >= F_CPU / 136) div = 136;
- else if (clock >= F_CPU / 137) div = 137;
- else if (clock >= F_CPU / 138) div = 138;
- else if (clock >= F_CPU / 139) div = 139;
- else if (clock >= F_CPU / 140) div = 140;
- else if (clock >= F_CPU / 141) div = 141;
- else if (clock >= F_CPU / 142) div = 142;
- else if (clock >= F_CPU / 143) div = 143;
- else if (clock >= F_CPU / 144) div = 144;
- else if (clock >= F_CPU / 145) div = 145;
- else if (clock >= F_CPU / 146) div = 146;
- else if (clock >= F_CPU / 147) div = 147;
- else if (clock >= F_CPU / 148) div = 148;
- else if (clock >= F_CPU / 149) div = 149;
- else if (clock >= F_CPU / 150) div = 150;
- else if (clock >= F_CPU / 151) div = 151;
- else if (clock >= F_CPU / 152) div = 152;
- else if (clock >= F_CPU / 153) div = 153;
- else if (clock >= F_CPU / 154) div = 154;
- else if (clock >= F_CPU / 155) div = 155;
- else if (clock >= F_CPU / 156) div = 156;
- else if (clock >= F_CPU / 157) div = 157;
- else if (clock >= F_CPU / 158) div = 158;
- else if (clock >= F_CPU / 159) div = 159;
- else if (clock >= F_CPU / 160) div = 160;
- else if (clock >= F_CPU / 161) div = 161;
- else if (clock >= F_CPU / 162) div = 162;
- else if (clock >= F_CPU / 163) div = 163;
- else if (clock >= F_CPU / 164) div = 164;
- else if (clock >= F_CPU / 165) div = 165;
- else if (clock >= F_CPU / 166) div = 166;
- else if (clock >= F_CPU / 167) div = 167;
- else if (clock >= F_CPU / 168) div = 168;
- else if (clock >= F_CPU / 169) div = 169;
- else if (clock >= F_CPU / 170) div = 170;
- else if (clock >= F_CPU / 171) div = 171;
- else if (clock >= F_CPU / 172) div = 172;
- else if (clock >= F_CPU / 173) div = 173;
- else if (clock >= F_CPU / 174) div = 174;
- else if (clock >= F_CPU / 175) div = 175;
- else if (clock >= F_CPU / 176) div = 176;
- else if (clock >= F_CPU / 177) div = 177;
- else if (clock >= F_CPU / 178) div = 178;
- else if (clock >= F_CPU / 179) div = 179;
- else if (clock >= F_CPU / 180) div = 180;
- else if (clock >= F_CPU / 181) div = 181;
- else if (clock >= F_CPU / 182) div = 182;
- else if (clock >= F_CPU / 183) div = 183;
- else if (clock >= F_CPU / 184) div = 184;
- else if (clock >= F_CPU / 185) div = 185;
- else if (clock >= F_CPU / 186) div = 186;
- else if (clock >= F_CPU / 187) div = 187;
- else if (clock >= F_CPU / 188) div = 188;
- else if (clock >= F_CPU / 189) div = 189;
- else if (clock >= F_CPU / 190) div = 190;
- else if (clock >= F_CPU / 191) div = 191;
- else if (clock >= F_CPU / 192) div = 192;
- else if (clock >= F_CPU / 193) div = 193;
- else if (clock >= F_CPU / 194) div = 194;
- else if (clock >= F_CPU / 195) div = 195;
- else if (clock >= F_CPU / 196) div = 196;
- else if (clock >= F_CPU / 197) div = 197;
- else if (clock >= F_CPU / 198) div = 198;
- else if (clock >= F_CPU / 199) div = 199;
- else if (clock >= F_CPU / 200) div = 200;
- else if (clock >= F_CPU / 201) div = 201;
- else if (clock >= F_CPU / 202) div = 202;
- else if (clock >= F_CPU / 203) div = 203;
- else if (clock >= F_CPU / 204) div = 204;
- else if (clock >= F_CPU / 205) div = 205;
- else if (clock >= F_CPU / 206) div = 206;
- else if (clock >= F_CPU / 207) div = 207;
- else if (clock >= F_CPU / 208) div = 208;
- else if (clock >= F_CPU / 209) div = 209;
- else if (clock >= F_CPU / 210) div = 210;
- else if (clock >= F_CPU / 211) div = 211;
- else if (clock >= F_CPU / 212) div = 212;
- else if (clock >= F_CPU / 213) div = 213;
- else if (clock >= F_CPU / 214) div = 214;
- else if (clock >= F_CPU / 215) div = 215;
- else if (clock >= F_CPU / 216) div = 216;
- else if (clock >= F_CPU / 217) div = 217;
- else if (clock >= F_CPU / 218) div = 218;
- else if (clock >= F_CPU / 219) div = 219;
- else if (clock >= F_CPU / 220) div = 220;
- else if (clock >= F_CPU / 221) div = 221;
- else if (clock >= F_CPU / 222) div = 222;
- else if (clock >= F_CPU / 223) div = 223;
- else if (clock >= F_CPU / 224) div = 224;
- else if (clock >= F_CPU / 225) div = 225;
- else if (clock >= F_CPU / 226) div = 226;
- else if (clock >= F_CPU / 227) div = 227;
- else if (clock >= F_CPU / 228) div = 228;
- else if (clock >= F_CPU / 229) div = 229;
- else if (clock >= F_CPU / 230) div = 230;
- else if (clock >= F_CPU / 231) div = 231;
- else if (clock >= F_CPU / 232) div = 232;
- else if (clock >= F_CPU / 233) div = 233;
- else if (clock >= F_CPU / 234) div = 234;
- else if (clock >= F_CPU / 235) div = 235;
- else if (clock >= F_CPU / 236) div = 236;
- else if (clock >= F_CPU / 237) div = 237;
- else if (clock >= F_CPU / 238) div = 238;
- else if (clock >= F_CPU / 239) div = 239;
- else if (clock >= F_CPU / 240) div = 240;
- else if (clock >= F_CPU / 241) div = 241;
- else if (clock >= F_CPU / 242) div = 242;
- else if (clock >= F_CPU / 243) div = 243;
- else if (clock >= F_CPU / 244) div = 244;
- else if (clock >= F_CPU / 245) div = 245;
- else if (clock >= F_CPU / 246) div = 246;
- else if (clock >= F_CPU / 247) div = 247;
- else if (clock >= F_CPU / 248) div = 248;
- else if (clock >= F_CPU / 249) div = 249;
- else if (clock >= F_CPU / 250) div = 250;
- else if (clock >= F_CPU / 251) div = 251;
- else if (clock >= F_CPU / 252) div = 252;
- else if (clock >= F_CPU / 253) div = 253;
- else if (clock >= F_CPU / 254) div = 254;
- else /* clock >= F_CPU / 255 */ div = 255;
- /*
- #! /usr/bin/perl
- for ($i=2; $i<256; $i++) {
- printf "\t\t\telse if (clock >= F_CPU / %3d) div = %3d;\n", $i, $i;
- }
- */
+ if (clock < (F_CPU / 255)) {
+ div = 255;
+ } else if (clock >= (F_CPU / 2)) {
+ div = 2;
} else {
- for (div=2; div<255; div++) {
- if (clock >= F_CPU / div) break;
- }
+ div = (F_CPU / (clock + 1)) + 1;
}
this->clockDiv = div;
this->dataMode = dataMode;
--
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