Faster checksum calculation

2 files changed, 35 insertions, 23 deletions

diff --git a/dumper.c b/dumper.c
index 6cab60e..c0ef773 100644
--- a/dumper.c
+++ b/dumper.c
@@ -63,7 +63,7 @@ ISR(USART0_RX_vect)
 static void set_address(unsigned int address)
 {
   unsigned char l = address & 0xFF;
-  unsigned char h = address>>8;
+  unsigned char h = (address >> 8) & 0xFF;
   
   PORTA = l;
   PORTC = h;
@@ -178,12 +178,20 @@ static void read_prg_crc_send(unsigned int address, unsigned int len)
 {
   LED_GREEN_ON;
   uint16_t crc = 0;
+  MODE_READ;
+  PRG_READ;  
+  PHI2_HI;
+  set_romsel(address); // set /ROMSEL low if need
   while (len > 0)
   {
-    crc = crc16_update(crc, read_prg_byte(address));
+    PORTA = address & 0xFF;
+    PORTC = (address >> 8) & 0xFF;
+    _delay_us(1);
+    crc = crc16_update(crc, PIND);
     len--;
     address++;
   }
+  ROMSEL_HI;
   set_address(0);
   comm_start(COMMAND_PRG_READ_RESULT, 2);
   comm_send_byte(crc & 0xFF);
diff --git a/famicom-dumper.hex b/famicom-dumper.hex
index 509d5cf..883ea2b 100644
--- a/famicom-dumper.hex
+++ b/famicom-dumper.hex
@@ -8,7 +8,7 @@
 :100070000C9458000C9458000C9458000C945800A0

 :100080000C9458000C9458000C94580011241FBE76

 :10009000CFEFD0E1DEBFCDBF29E0A0E0B1E001C0ED

-:1000A0001D92A531B207E1F70E9414030C94430896

+:1000A0001D92A531B207E1F70E9414030C94620877

 :1000B0000C9400008BBB95BB95FD06C0809162003F

 :1000C0008061809362000895809162008F7E8093AA

 :1000D00062000895CF93DF93C2E6D0E028812E7F9F

@@ -102,7 +102,7 @@
 :1006500082BB11BA1BBA15BA909162009061909357

 :1006600062008ABB84BBBC98C498C798C6980E9495

 :100670000B0360E070E080E00E94390277247394FD

-:100680000EE6C02ED12C84E1482E512C66246A94AB

+:100680001EE6C12ED12C04E1402E512C66246A9422

 :100690008FB589628FBD21E02EBD20E030E0E0E023

 :1006A00041E050E060E070E080910B01811135C0C5

 :1006B0008FB589628FBD7EBC403187E258076105E6

@@ -152,8 +152,8 @@
 :100970006200809162008160809362002FEFE21A32

 :10098000F20A49815A81415051095A834983452BC2

 :1009900039F6C79860E070E08EE00E94390278CEA8

-:1009A000E0900D0180910E01F12CF82A30910F0199

-:1009B000398380911001432F50E0582B5A8349838B

+:1009A000E0900D0180910E01F12CF82A20910F01A9

+:1009B000298380911001422F50E0582B5A8349839C

 :1009C000C79A452B99F001E111E0F80161918F017F

 :1009D000C7010E94E300FFEFEF1AFF0A29813A8165

 :1009E000215031093A832983232B79F7C79860E096

@@ -185,7 +185,7 @@
 :100B80008B819C810E948A00882E8B819C810E948F

 :100B90008A00982E8B819C810E948A00382E882D95

 :100BA000892586FF18C0892D832586FF14C081FC06

-:100BB00060C285FEDFCF63E070E08AE20E94390206

+:100BB00078C285FEDFCF63E070E08AE20E943902EE

 :100BC000882D0E946102892D0E946102832D0E945E

 :100BD0006102C7985DCD8B819C810E948A00982E0E

 :100BE0008B819C810E948A009812C4CFE981FA818E

@@ -199,7 +199,7 @@
 :100C6000B0001DBC1CBC8CB59DB58D389B45D0F427

 :100C700080E090E80E948A0089838CB59DB58D380C

 :100C80009B4580F480E090E80E948A008B83598124

-:100C90005827547409F4DFC189838CB59DB58D380C

+:100C90005827547409F4F7C189838CB59DB58D38F4

 :100CA0009B4580F360E070E08CE20E943902C798B7

 :100CB000EFCCC79AC69A809162008E7F80936200C3

 :100CC00080916200826080936200FFEF20E732E053

@@ -235,13 +235,13 @@
 :100EA000415051095A8349838CB59DB584389E4180

 :100EB00008F0ACCEC7010E943801882EC7010E94FD

 :100EC0003801982EC7010E943801382E882D8925B7

-:100ED00086FF09C0892D832586FF05C081FCC9C016

+:100ED00086FF09C0892D832586FF05C081FCE1C0FE

 :100EE00085FEE2CF68CEC7010E943801982EC70167

 :100EF0000E9438019812D8CFE981FA818081981236

 :100F0000D3CF2B813C81232B09F660E070E08AE08F

 :100F10000E943902C798BCCBE0900D0180910E0170

 :100F2000F12CF82A00910F018091100110E0182B8C

-:100F3000C69A0115110509F4A3C01A821982C701C6

+:100F3000C69A0115110509F4C2C01A821982C701A7

 :100F40000E946A0029813A8128273A83298388E010

 :100F500090E00CC049815A8156954795E1E04E27B3

 :100F6000E0EA5E275A834983019759F0398130FDC1

@@ -250,17 +250,21 @@
 :100F9000B1F619814A8149831BBA15BA8091620062

 :100FA00080618093620062E070E08CE00E94390210

 :100FB000812F0E94610289810E946102C69868CBDC

-:100FC000E0900D0180910E01F12CF82A00910F01A3

-:100FD0008091100110E0182BC69A0115110509F433

-:100FE0004CC01A821982C7010E943801E981FA8136

-:100FF000E827FA83E98388E090E00CC029813A81F0

-:101000003695279541E0242740EA34273A832983FF

-:10101000019759F0F981F0FDF1CFE981FA81F69558

-:10102000E795FA83E9830197A9F701501109FFEFCA

-:10103000EF1AFF0A01151105B1F619812A812983DA

-:101040001BBA15BA8091620080618093620062E0F1

-:1010500070E088E0ABCFFB81FF3F09F4D0CD61E0C9

-:1010600070E08BE20E9439028B810E946102C79876

-:101070000FCB63E070E089E2A1CD198210E0E0CFF0

-:0A108000198210E089CFF894FFCF29

+:100FC00040910D0180910E0150E0582B60910F016E

+:100FD0008091100170E0782BC69A62BA11BA8091A4

+:100FE00062008068809362008091620081608093DB

+:100FF00062008091620057FD58C082608093620059

+:101000006115710509F458C080E090E04BBB55BBF9

+:10101000E2E0EA95F1F700C020B3822728E030E053

+:1010200009C096958795F1E08F27F0EA9F27215018

+:10103000310939F080FDF5CF96958795215031091A

+:10104000C9F7615071094F5F5F4F61157105F1F686

+:101050008B839983809162008260809362001BBAC7

+:1010600015BA8091620080618093620062E070E056

+:1010700088E00E9439028B810E94610289810E946E

+:101080006102C69805CBFB81FF3F09F4B8CD61E052

+:1010900070E08BE20E9439028B810E946102C79846

+:1010A000F7CA63E070E089E289CD8D7F80936200AA

+:1010B0006115710509F0A8CF19821B82CBCF198267

+:0810C00010E06ACFF894FFCFA5

 :00000001FF