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 a0fa50d3a3bc23c68ba7d41d44db749297adf63e..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 * 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
@@ -416,8 +421,11 @@ 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;
@@ -425,6 +433,8 @@ void ResetSspClk(void) {
        AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
        while (AT91C_BASE_TC2->TC_CV > 0);
 }
+
+
 uint32_t RAMFUNC GetCountSspClk(){
        uint32_t tmp_count;
        tmp_count = (AT91C_BASE_TC2->TC_CV << 16) | AT91C_BASE_TC0->TC_CV;
@@ -436,6 +446,7 @@ uint32_t RAMFUNC GetCountSspClk(){
        }
 }
 
+
 //  -------------------------------------------------------------------------
 //  Timer for bitbanging,  or LF stuff when you need a very precis timer
 //  1us = 1.5ticks
@@ -464,6 +475,7 @@ void StartTicks(void){
        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){
@@ -471,32 +483,43 @@ void WaitTicks(uint32_t ticks){
        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 * 1.5) );
+       WaitTicks( (uint32_t)us * 3 / 2 ) ;
 }
+
+
 void WaitMS(uint16_t ms){
        if (ms == 0) return;
-       WaitTicks( (uint32_t)(ms * 1500) );
+       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.
@@ -512,4 +535,3 @@ uint32_t prand() {
        next_random = next_random * 6364136223846793005 + 1;
        return (uint32_t)(next_random >> 32) % 0xffffffff;
 }
-