save 2.3K flash-memory by avoiding a single floating point operation (#630)

[proxmark3-svn] / armsrc / util.c

diff --git a/armsrc/util.c b/armsrc/util.c
index 1dd8dc7544fe1cb2989548692f8449f19b6ca621..59dfe07b45987250ae74b0495de38636e293560d 100644 (file)
--- a/armsrc/util.c
+++ b/armsrc/util.c
@@ -292,6 +292,7 @@ void FormatVersionInformation(char *dst, int len, const char *prefix, void *vers
        strncat(dst, "\n", len - strlen(dst) - 1);
 }
 
+
 //  -------------------------------------------------------------------------
 //  timer lib
 //  -------------------------------------------------------------------------
@@ -312,6 +313,7 @@ void StartTickCount()
        // note: worst case precision is approx 2.5%
 }
 
+
 /*
 * Get the current count.
 */
@@ -319,6 +321,7 @@ uint32_t RAMFUNC GetTickCount(){
        return AT91C_BASE_RTTC->RTTC_RTVR;// was * 2;
 }
 
+
 //  -------------------------------------------------------------------------
 //  microseconds timer 
 //  -------------------------------------------------------------------------
@@ -344,10 +347,12 @@ void StartCountUS()
        AT91C_BASE_TCB->TCB_BCR = 1;
        }
 
+
 uint32_t RAMFUNC GetCountUS(){
-       return (AT91C_BASE_TC1->TC_CV * 0x8000) + ((AT91C_BASE_TC0->TC_CV / 15) * 10);
+       return (AT91C_BASE_TC1->TC_CV * 0x8000) + ((AT91C_BASE_TC0->TC_CV * 2) / 3); //was  /15) * 10);
 }
 
+
 static uint32_t GlobalUsCounter = 0;
 
 uint32_t RAMFUNC GetDeltaCountUS(){
@@ -402,7 +407,7 @@ void StartCountSspClk()
        AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN;                                // enable TC2
 
        //
-       // synchronize the counter with the ssp_frame signal. Note: FPGA must be in any iso14446 mode, otherwise the frame signal would not be present 
+       // synchronize the counter with the ssp_frame signal. Note: FPGA must be in any iso14443 mode, otherwise SSC_FRAME and SSC_CLK signals would not be present 
        //
        while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME));   // wait for ssp_frame to go high (start of frame)
        while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME);              // wait for ssp_frame to be low
@@ -416,7 +421,17 @@ void StartCountSspClk()
        // (just started with the transfer of the 4th Bit).
        // The high word of the counter (TC2) will not reset until the low word (TC0) overflows. Therefore need to wait quite some time before
        // we can use the counter.
-       while (AT91C_BASE_TC0->TC_CV < 0xFFF0);
+       while (AT91C_BASE_TC0->TC_CV < 0xFFFF);
+       // Note: needs one more SSP_CLK cycle (1.18 us) until TC2 resets. Don't call GetCountSspClk() that soon.
+}
+
+
+void ResetSspClk(void) {
+       //enable clock of timer and software trigger
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       while (AT91C_BASE_TC2->TC_CV > 0);
 }
 
 
@@ -431,3 +446,92 @@ uint32_t RAMFUNC GetCountSspClk(){
        }
 }
 
+
+//  -------------------------------------------------------------------------
+//  Timer for bitbanging,  or LF stuff when you need a very precis timer
+//  1us = 1.5ticks
+//  -------------------------------------------------------------------------
+void StartTicks(void){
+       //initialization of the timer
+       // tc1 is higher 0xFFFF0000
+       // tc0 is lower 0x0000FFFF
+       AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1);
+       AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
+       AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz) / 32 
+                                                               AT91C_TC_WAVE | AT91C_TC_WAVESEL_UP_AUTO | AT91C_TC_ACPA_CLEAR |
+                                                               AT91C_TC_ACPC_SET | AT91C_TC_ASWTRG_SET;
+       AT91C_BASE_TC0->TC_RA = 1;
+       AT91C_BASE_TC0->TC_RC = 0; 
+
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;       // timer disable  
+       AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_XC1; // from TC0
+       
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       AT91C_BASE_TCB->TCB_BCR = 1;
+       
+       // wait until timer becomes zero.
+       while (AT91C_BASE_TC1->TC_CV > 0);
+}
+
+
+// Wait - Spindelay in ticks.
+// if called with a high number, this will trigger the WDT...
+void WaitTicks(uint32_t ticks){
+       if ( ticks == 0 ) return;
+       ticks += GET_TICKS;     
+       while (GET_TICKS < ticks);
+}
+
+
+// Wait / Spindelay in us (microseconds) 
+// 1us = 1.5ticks.
+void WaitUS(uint16_t us){
+       if ( us == 0 ) return;
+       WaitTicks( (uint32_t)us * 3 / 2 ) ;
+}
+
+
+void WaitMS(uint16_t ms){
+       if (ms == 0) return;
+       WaitTicks( (uint32_t)ms * 1500 );
+}
+
+
+// Starts Clock and waits until its reset
+void ResetTicks(void){
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       while (AT91C_BASE_TC1->TC_CV > 0);
+}
+
+
+void ResetTimer(AT91PS_TC timer){
+       timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       while(timer->TC_CV > 0) ;
+}
+
+
+// stop clock
+void StopTicks(void){
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;       
+}
+
+
+static uint64_t next_random = 1;
+
+/* Generates a (non-cryptographically secure) 32-bit random number.
+ *
+ * We don't have an implementation of the "rand" function or a clock to seed it
+ * with, so we just call GetTickCount the first time to seed ourselves.
+ */
+uint32_t prand() {
+       if (next_random == 1) {
+               next_random = GetTickCount();
+       }
+
+       next_random = next_random * 6364136223846793005 + 1;
+       return (uint32_t)(next_random >> 32) % 0xffffffff;
+}