From 3cec706139a331d4405db6a7d71e17e0a1573c20 Mon Sep 17 00:00:00 2001
From: marshmellow42 <marshmellowrf@gmail.com>
Date: Sat, 20 Feb 2016 10:07:44 -0500
Subject: [PATCH] move the clear buffer outside of potentially time..

... sensitive routines
see http://www.proxmark.org/forum/viewtopic.php?id=2820
---
 armsrc/BigBuf.c     |  4 ++++
 armsrc/BigBuf.h     |  1 +
 armsrc/lfops.c      | 11 +++++++++++
 armsrc/lfsampling.c |  2 +-
 armsrc/pcf7931.c    |  2 ++
 5 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/armsrc/BigBuf.c b/armsrc/BigBuf.c
index da3b0ce2..851cf390 100644
--- a/armsrc/BigBuf.c
+++ b/armsrc/BigBuf.c
@@ -61,6 +61,10 @@ void BigBuf_Clear_ext(bool verbose)
 		Dbprintf("Buffer cleared (%i bytes)",BIGBUF_SIZE);
 }
 
+void BigBuf_Clear_keep_EM(void)
+{
+	memset(BigBuf,0,BigBuf_hi);
+}
 
 // allocate a chunk of memory from BigBuf. We allocate high memory first. The unallocated memory
 // at the beginning of BigBuf is always for traces/samples
diff --git a/armsrc/BigBuf.h b/armsrc/BigBuf.h
index 13432e7e..11e02c7a 100644
--- a/armsrc/BigBuf.h
+++ b/armsrc/BigBuf.h
@@ -26,6 +26,7 @@ extern uint8_t *BigBuf_get_EM_addr(void);
 extern uint16_t BigBuf_max_traceLen(void);
 extern void BigBuf_Clear(void);
 extern void BigBuf_Clear_ext(bool verbose);
+extern void BigBuf_Clear_keep_EM(void);
 extern uint8_t *BigBuf_malloc(uint16_t);
 extern void BigBuf_free(void);
 extern void BigBuf_free_keep_EM(void);
diff --git a/armsrc/lfops.c b/armsrc/lfops.c
index 47fec7c2..bb298f79 100644
--- a/armsrc/lfops.c
+++ b/armsrc/lfops.c
@@ -37,6 +37,8 @@ void ModThenAcquireRawAdcSamples125k(uint32_t delay_off, uint32_t period_0, uint
 
 	sample_config sc = { 0,0,1, divisor_used, 0};
 	setSamplingConfig(&sc);
+	//clear read buffer
+	BigBuf_Clear_keep_EM(void);
 
 	/* Make sure the tag is reset */
 	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
@@ -752,6 +754,9 @@ void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
 	// Configure to go in 125Khz listen mode
 	LFSetupFPGAForADC(95, true);
 
+	//clear read buffer
+	BigBuf_Clear_keep_EM(void);
+
 	while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
 
 		WDT_HIT();
@@ -837,6 +842,8 @@ void CmdAWIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
 	uint8_t *dest = BigBuf_get_addr();
 	size_t size; 
 	int idx=0;
+	//clear read buffer
+	BigBuf_Clear_keep_EM(void);
 	// Configure to go in 125Khz listen mode
 	LFSetupFPGAForADC(95, true);
 
@@ -927,6 +934,8 @@ void CmdEM410xdemod(int findone, int *high, int *low, int ledcontrol)
 	int clk=0, invert=0, errCnt=0, maxErr=20;
 	uint32_t hi=0;
 	uint64_t lo=0;
+	//clear read buffer
+	BigBuf_Clear_keep_EM(void);
 	// Configure to go in 125Khz listen mode
 	LFSetupFPGAForADC(95, true);
 
@@ -986,6 +995,8 @@ void CmdIOdemodFSK(int findone, int *high, int *low, int ledcontrol)
 	uint8_t version=0;
 	uint8_t facilitycode=0;
 	uint16_t number=0;
+	//clear read buffer
+	BigBuf_Clear_keep_EM(void);
 	// Configure to go in 125Khz listen mode
 	LFSetupFPGAForADC(95, true);
 
diff --git a/armsrc/lfsampling.c b/armsrc/lfsampling.c
index ab7c79dd..88df543f 100644
--- a/armsrc/lfsampling.c
+++ b/armsrc/lfsampling.c
@@ -124,7 +124,7 @@ uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averag
 	uint8_t *dest = BigBuf_get_addr();
     int bufsize = BigBuf_max_traceLen();
 
-	memset(dest, 0, bufsize);
+	//memset(dest, 0, bufsize); //creates issues with cmdread (marshmellow)
 
 	if(bits_per_sample < 1) bits_per_sample = 1;
 	if(bits_per_sample > 8) bits_per_sample = 8;
diff --git a/armsrc/pcf7931.c b/armsrc/pcf7931.c
index 3093a5e5..73f18768 100644
--- a/armsrc/pcf7931.c
+++ b/armsrc/pcf7931.c
@@ -29,6 +29,8 @@ int DemodPCF7931(uint8_t **outBlocks) {
 	int num_blocks = 0;
 	int lmin=128, lmax=128;
 	uint8_t dir;
+	//clear read buffer
+	BigBuf_Clear_keep_EM(void);
 
 	LFSetupFPGAForADC(95, true);
 	DoAcquisition_default(0, true);
-- 
2.39.5