X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/e30c654b196a87a13ae7f7d4ced930b296c038ec..refs/pull/938/head:/armsrc/util.c diff --git a/armsrc/util.c b/armsrc/util.c index ae2e7247..b0cd1818 100644 --- a/armsrc/util.c +++ b/armsrc/util.c @@ -1,78 +1,61 @@ //----------------------------------------------------------------------------- -// Utility functions used in many places, not specific to any piece of code. // Jonathan Westhues, Sept 2005 +// +// This code is licensed to you under the terms of the GNU GPL, version 2 or, +// at your option, any later version. See the LICENSE.txt file for the text of +// the license. +//----------------------------------------------------------------------------- +// Utility functions used in many places, not specific to any piece of code. //----------------------------------------------------------------------------- + #include "proxmark3.h" +#include "util.h" +#include "string.h" #include "apps.h" - -void *memcpy(void *dest, const void *src, int len) -{ - BYTE *d = dest; - const BYTE *s = src; - while((len--) > 0) { - *d = *s; - d++; - s++; - } - return dest; +#include "BigBuf.h" + + + +void print_result(char *name, uint8_t *buf, size_t len) { + uint8_t *p = buf; + + if ( len % 16 == 0 ) { + for(; p-buf < len; p += 16) + Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x", + name, + p-buf, + len, + p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15] + ); + } + else { + for(; p-buf < len; p += 8) + Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x", name, p-buf, len, p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]); + } } -void *memset(void *dest, int c, int len) -{ - BYTE *d = dest; - while((len--) > 0) { - *d = c; - d++; - } - return dest; +size_t nbytes(size_t nbits) { + return (nbits >> 3)+((nbits % 8) > 0); } -int memcmp(const void *av, const void *bv, int len) -{ - const BYTE *a = av; - const BYTE *b = bv; - - while((len--) > 0) { - if(*a != *b) { - return *a - *b; - } - a++; - b++; +uint32_t SwapBits(uint32_t value, int nrbits) { + int i; + uint32_t newvalue = 0; + for(i = 0; i < nrbits; i++) { + newvalue ^= ((value >> i) & 1) << (nrbits - 1 - i); } - return 0; + return newvalue; } -int strlen(char *str) -{ - int l = 0; - while(*str) { - l++; - str++; - } - return l; -} - -char* strncat(char *dest, const char *src, unsigned int n) -{ - unsigned int dest_len = strlen(dest); - unsigned int i; - - for (i = 0 ; i < n && src[i] != '\0' ; i++) - dest[dest_len + i] = src[i]; - dest[dest_len + i] = '\0'; - - return dest; -} - -void num_to_bytes(uint64_t n, size_t len, byte_t* dest) +void num_to_bytes(uint64_t n, size_t len, uint8_t* dest) { while (len--) { - dest[len] = (byte_t) n; + dest[len] = (uint8_t) n; n >>= 8; } } -uint64_t bytes_to_num(byte_t* src, size_t len) +uint64_t bytes_to_num(uint8_t* src, size_t len) { uint64_t num = 0; while (len--) @@ -83,6 +66,21 @@ uint64_t bytes_to_num(byte_t* src, size_t len) return num; } +// RotateLeft - Ultralight, Desfire +void rol(uint8_t *data, const size_t len){ + uint8_t first = data[0]; + for (size_t i = 0; i < len-1; i++) { + data[i] = data[i+1]; + } + data[len-1] = first; +} +void lsl (uint8_t *data, size_t len) { + for (size_t n = 0; n < len - 1; n++) { + data[n] = (data[n] << 1) | (data[n+1] >> 7); + } + data[len - 1] <<= 1; +} + void LEDsoff() { LED_A_OFF(); @@ -91,6 +89,22 @@ void LEDsoff() LED_D_OFF(); } +void LEDson() +{ + LED_A_ON(); + LED_B_ON(); + LED_C_ON(); + LED_D_ON(); +} + +void LEDsinvert() +{ + LED_A_INV(); + LED_B_INV(); + LED_C_INV(); + LED_D_INV(); +} + // LEDs: R(C) O(A) G(B) -- R(D) [1, 2, 4 and 8] void LED(int led, int ms) { @@ -123,8 +137,7 @@ void LED(int led, int ms) // not clicked, or held down (for ms || 1sec) // In general, don't use this function unless you expect a // double click, otherwise it will waste 500ms -- use BUTTON_HELD instead -int BUTTON_CLICKED(int ms) -{ +int BUTTON_CLICKED(int ms) { // Up to 500ms in between clicks to mean a double click int ticks = (48000 * (ms ? ms : 1000)) >> 10; @@ -139,12 +152,12 @@ int BUTTON_CLICKED(int ms) AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; - WORD start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + uint16_t start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; int letoff = 0; for(;;) { - WORD now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + uint16_t now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; // We haven't let off the button yet if (!letoff) @@ -162,7 +175,7 @@ int BUTTON_CLICKED(int ms) // Still haven't let it off else // Have we held down a full second? - if (now == (WORD)(start + ticks)) + if (now == (uint16_t)(start + ticks)) return BUTTON_HOLD; } @@ -174,7 +187,7 @@ int BUTTON_CLICKED(int ms) // Have we ran out of time to double click? else - if (now == (WORD)(start + ticks)) + if (now == (uint16_t)(start + ticks)) // At least we did a single click return BUTTON_SINGLE_CLICK; @@ -186,8 +199,7 @@ int BUTTON_CLICKED(int ms) } // Determine if a button is held down -int BUTTON_HELD(int ms) -{ +int BUTTON_HELD(int ms) { // If button is held for one second int ticks = (48000 * (ms ? ms : 1000)) >> 10; @@ -202,19 +214,17 @@ int BUTTON_HELD(int ms) AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; - WORD start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + uint16_t start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - for(;;) - { - WORD now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + for(;;) { + uint16_t now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; // As soon as our button let go, we didn't hold long enough if (!BUTTON_PRESS()) return BUTTON_SINGLE_CLICK; // Have we waited the full second? - else - if (now == (WORD)(start + ticks)) + else if (now == (uint16_t)(start + ticks)) return BUTTON_HOLD; WDT_HIT(); @@ -226,8 +236,7 @@ int BUTTON_HELD(int ms) // attempt at high resolution microsecond timer // beware: timer counts in 21.3uS increments (1024/48Mhz) -void SpinDelayUs(int us) -{ +void SpinDelayUs(int us) { int ticks = (48*us) >> 10; // Borrow a PWM unit for my real-time clock @@ -237,19 +246,18 @@ void SpinDelayUs(int us) AT91C_BASE_PWMC_CH0->PWMC_CDTYR = 0; AT91C_BASE_PWMC_CH0->PWMC_CPRDR = 0xffff; - WORD start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + uint16_t start = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; for(;;) { - WORD now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; - if (now == (WORD)(start + ticks)) + uint16_t now = AT91C_BASE_PWMC_CH0->PWMC_CCNTR; + if (now == (uint16_t)(start + ticks)) return; WDT_HIT(); } } -void SpinDelay(int ms) -{ +void SpinDelay(int ms) { // convert to uS and call microsecond delay function SpinDelayUs(ms*1000); } @@ -263,27 +271,297 @@ void FormatVersionInformation(char *dst, int len, const char *prefix, void *vers { struct version_information *v = (struct version_information*)version_information; dst[0] = 0; - strncat(dst, prefix, len); + strncat(dst, prefix, len-1); if(v->magic != VERSION_INFORMATION_MAGIC) { - strncat(dst, "Missing/Invalid version information", len); + strncat(dst, "Missing/Invalid version information\n", len - strlen(dst) - 1); return; } if(v->versionversion != 1) { - strncat(dst, "Version information not understood", len); + strncat(dst, "Version information not understood\n", len - strlen(dst) - 1); return; } if(!v->present) { - strncat(dst, "Version information not available", len); + strncat(dst, "Version information not available\n", len - strlen(dst) - 1); return; } - strncat(dst, v->svnversion, len); + strncat(dst, v->gitversion, len - strlen(dst) - 1); if(v->clean == 0) { - strncat(dst, "-unclean", len); + strncat(dst, "-unclean", len - strlen(dst) - 1); } else if(v->clean == 2) { - strncat(dst, "-suspect", len); + strncat(dst, "-suspect", len - strlen(dst) - 1); + } + + strncat(dst, " ", len - strlen(dst) - 1); + strncat(dst, v->buildtime, len - strlen(dst) - 1); + strncat(dst, "\n", len - strlen(dst) - 1); +} + + +// ------------------------------------------------------------------------- +// timer lib +// ------------------------------------------------------------------------- +// test procedure: +// +// ti = GetTickCount(); +// SpinDelay(1000); +// ti = GetTickCount() - ti; +// Dbprintf("timer(1s): %d t=%d", ti, GetTickCount()); + +void StartTickCount() { + // This timer is based on the slow clock. The slow clock frequency is between 22kHz and 40kHz. + // We can determine the actual slow clock frequency by looking at the Main Clock Frequency Register. + uint16_t mainf = AT91C_BASE_PMC->PMC_MCFR & 0xffff; // = 16 * main clock frequency (16MHz) / slow clock frequency + // set RealTimeCounter divider to count at 1kHz: + AT91C_BASE_RTTC->RTTC_RTMR = AT91C_RTTC_RTTRST | ((256000 + (mainf/2)) / mainf); + // note: worst case precision is approx 2.5% +} + + +/* +* Get the current count. +*/ +uint32_t RAMFUNC GetTickCount(void) { + return AT91C_BASE_RTTC->RTTC_RTVR;// was * 2; +} + + +// ------------------------------------------------------------------------- +// microseconds timer +// ------------------------------------------------------------------------- +void StartCountUS(void) { + AT91C_BASE_PMC->PMC_PCER |= (0x1 << 12) | (0x1 << 13) | (0x1 << 14); +// AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC1XC1S_TIOA0; + AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE; + + // fast clock + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable + AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz)/32 -- tick=1.5mks + 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 = 0xBFFF + 1; // 0xC000 + + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // timer disable + AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_XC1; // from timer 0 + + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN; + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN; + AT91C_BASE_TCB->TCB_BCR = 1; + } + + +uint32_t RAMFUNC GetCountUS(void) { + 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(void) { + uint32_t g_cnt = GetCountUS(); + uint32_t g_res = g_cnt - GlobalUsCounter; + GlobalUsCounter = g_cnt; + return g_res; +} + + +// ------------------------------------------------------------------------- +// Timer for iso14443 commands. Uses ssp_clk from FPGA +// ------------------------------------------------------------------------- +void StartCountSspClk(void) { + AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1) | (1 << AT91C_ID_TC2); // Enable Clock to all timers + AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_TIOA1 // XC0 Clock = TIOA1 + | AT91C_TCB_TC1XC1S_NONE // XC1 Clock = none + | AT91C_TCB_TC2XC2S_TIOA0; // XC2 Clock = TIOA0 + + // configure TC1 to create a short pulse on TIOA1 when a rising edge on TIOB1 (= ssp_clk from FPGA) occurs: + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // disable TC1 + AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK // TC1 Clock = MCK(48MHz)/2 = 24MHz + | AT91C_TC_CPCSTOP // Stop clock on RC compare + | AT91C_TC_EEVTEDG_RISING // Trigger on rising edge of Event + | AT91C_TC_EEVT_TIOB // Event-Source: TIOB1 (= ssp_clk from FPGA = 13,56MHz/16 ... 13,56MHz/4) + | AT91C_TC_ENETRG // Enable external trigger event + | AT91C_TC_WAVESEL_UP // Upmode without automatic trigger on RC compare + | AT91C_TC_WAVE // Waveform Mode + | AT91C_TC_AEEVT_SET // Set TIOA1 on external event + | AT91C_TC_ACPC_CLEAR; // Clear TIOA1 on RC Compare + AT91C_BASE_TC1->TC_RC = 1; // RC Compare value = 1; pulse width to TC0 + + // use TC0 to count TIOA1 pulses + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // disable TC0 + AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_XC0 // TC0 clock = XC0 clock = TIOA1 + | AT91C_TC_WAVE // Waveform Mode + | AT91C_TC_WAVESEL_UP // just count + | AT91C_TC_ACPA_CLEAR // Clear TIOA0 on RA Compare + | AT91C_TC_ACPC_SET; // Set TIOA0 on RC Compare + AT91C_BASE_TC0->TC_RA = 1; // RA Compare value = 1; pulse width to TC2 + AT91C_BASE_TC0->TC_RC = 0; // RC Compare value = 0; increment TC2 on overflow + + // use TC2 to count TIOA0 pulses (giving us a 32bit counter (TC0/TC2) clocked by ssp_clk) + AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKDIS; // disable TC2 + AT91C_BASE_TC2->TC_CMR = AT91C_TC_CLKS_XC2 // TC2 clock = XC2 clock = TIOA0 + | AT91C_TC_WAVE // Waveform Mode + | AT91C_TC_WAVESEL_UP; // just count + + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN; // enable TC0 + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN; // enable TC1 + AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN; // enable TC2 + + // + // synchronize the counter with the ssp_frame signal. Note: FPGA must be in a FPGA mode with SSC transfer, 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 be low + 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_CLK)); // wait for ssp_clk to go high; 1st ssp_clk after start of frame + while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low; + while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 2nd ssp_clk after start of frame + if ((AT91C_BASE_SSC->SSC_RFMR & SSC_FRAME_MODE_BITS_IN_WORD(32)) == SSC_FRAME_MODE_BITS_IN_WORD(16)) { // 16bit frame + while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low; + while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 3rd ssp_clk after start of frame + while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low; + while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 4th ssp_clk after start of frame + while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low; + while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 5th ssp_clk after start of frame + while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK); // wait for ssp_clk to go low; + while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 6th ssp_clk after start of frame + } + // it is now safe to assert a sync signal. This sets all timers to 0 on next active clock edge + AT91C_BASE_TCB->TCB_BCR = 1; // assert Sync (set all timers to 0 on next active clock edge) + // at the next (3rd/7th) ssp_clk rising edge, TC1 will be reset (and not generate a clock signal to TC0) + // at the next (4th/8th) ssp_clk rising edge, TC0 (the low word of our counter) will be reset. From now on, + // whenever the last three/four bits of our counter go 0, we can be sure to be in the middle of a frame transfer. + + // 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 < 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); +} + +uint32_t GetCountSspClk(){ + uint32_t hi, lo; + + do { + hi = AT91C_BASE_TC2->TC_CV; + lo = AT91C_BASE_TC0->TC_CV; + } while (hi != AT91C_BASE_TC2->TC_CV); + + return (hi << 16) | lo; +} + +// ------------------------------------------------------------------------- +// Timer for bitbanging, or LF stuff when you need a very precis timer +// 1us = 1.5ticks +// ------------------------------------------------------------------------- +void StartTicks(void){ + // initialization of the timer + 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; + + // disable TC0 and TC1 for re-configuration + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + + // first configure TC1 (higher, 0xFFFF0000) 16 bit counter + AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_XC1; // just connect to TIOA0 from TC0 + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // re-enable timer and wait for TC0 + + // second configure TC0 (lower, 0x0000FFFF) 16 bit counter + 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 | // RA comperator clears TIOA (carry bit) + AT91C_TC_ACPC_SET | // RC comperator sets TIOA (carry bit) + AT91C_TC_ASWTRG_SET; // SWTriger sets TIOA (carry bit) + AT91C_BASE_TC0->TC_RC = 0; // set TIOA (carry bit) on overflow, return to zero + AT91C_BASE_TC0->TC_RA = 1; // clear carry bit on next clock cycle + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // reset and re-enable timer + + // synchronized startup procedure + while (AT91C_BASE_TC0->TC_CV > 0); // wait until TC0 returned to zero + while (AT91C_BASE_TC0->TC_CV < 2); // and has started (TC_CV > TC_RA, now TC1 is cleared) + + // return to zero + AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; + AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; + while (AT91C_BASE_TC0->TC_CV > 0); +} + + +uint32_t GetTicks(void) { + uint32_t hi, lo; + + do { + hi = AT91C_BASE_TC1->TC_CV; + lo = AT91C_BASE_TC0->TC_CV; + } while(hi != AT91C_BASE_TC1->TC_CV); + + return (hi << 16) | lo; +} + + +// 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 += GetTicks(); + while (GetTicks() < ticks); +} + + +// Wait / Spindelay in us (microseconds) +// 1us = 1.5ticks. +void WaitUS(uint16_t us){ + WaitTicks( (uint32_t)us * 3 / 2 ) ; +} + + +void WaitMS(uint16_t ms){ + WaitTicks( (uint32_t)ms * 1500 ); +} + + +// Starts Clock and waits until its reset +void ResetTicks(void){ + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + while (AT91C_BASE_TC0->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(); } - strncat(dst, " ", len); - strncat(dst, v->buildtime, len); + next_random = next_random * 6364136223846793005 + 1; + return (uint32_t)(next_random >> 32) % 0xffffffff; }