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https://github.com/sqlite/sqlite.git
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Simplify the implementation of sqlite3GetVarint().
FossilOrigin-Name: d3dfaeb8b901d290c14b46c9e2970cc6a17a7bba2637bfdd353f49bcf41bd0dc
This commit is contained in:
drh
15
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15
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@@ -1,5 +1,5 @@
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C Create\sa\snew\svarint\sdecoder\sthat\sdoes\snot\sneed\sto\sreturn\sthe\ssize\sof\sthe\nvarint,\sand\suse\sthat\sin\ssqlite3BtreeTableMoveto().\s\sOmit\sthe\spointless\ngetVarint\sand\sputVarint\smacros\sand\suse\sthe\sactual\sfunction\snames\sinstead.
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D 2026-08-12T19:42:02.714
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C Simplify\sthe\simplementation\sof\ssqlite3GetVarint().
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D 2026-08-12T20:04:07.232
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F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
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F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
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F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
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@@ -807,7 +807,7 @@ F src/trigger.c 74bc99aaa36dc820481960d4cde3cd7f060964525deebd527eee55ac3b6a2895
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F src/update.c 3e5e7ff66fa19ebe4d1b113d480639a24cc1175adbefabbd1a948a07f28e37cf
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F src/upsert.c dd9f0fcccbfb4f20e1026a21a7254ba3f2c08e9cfa92affaff5b5ec3b00ea549
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F src/utf.c 7267c3fb9e2467020507601af3354c2446c61f444387e094c779dccd5ca62165
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F src/util.c 36970e81f236520d8c251c791acab8825280daaa8068a23ba834e65e0ddf986d
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F src/util.c cfdf9c6e5323af886d5ce766709da607ba1d14193ad3a15f4f462a45420e8211
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F src/vacuum.c d3d35d8ae893d419ade5fa196d761a83bddcbb62137a1a157ae751ef38b26e82
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F src/vdbe.c e1e84712a15e9a126ea5b6bb0689c28569d8421c80104bb20c1acac04d86edf4
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F src/vdbe.h 70e862ac8a11b590f8c1eaac17a0078429d42bc4ea3f757a9af0f451dd966a71
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@@ -2218,11 +2218,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
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F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
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F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
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F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
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P bc57a14ab92dd8c247a893cf4cec7c0dccaa7e8407854a63aa3af699c60bacd5
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R 4b8dd99e5eb110bdce1a955655fb0d11
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T *branch * varint-decode
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T *sym-varint-decode *
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T -sym-trunk *
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P f845ede54c065ebd222f3f3488f655f2cbbf2c40bae782b3f4eac76cbb0525ad
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R 0a5a5987e95f916d15c138e1832779bb
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U drh
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Z ff7c33ab682d53337cbbfd8d9584b7b5
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Z dae75b8b511d421e3405d86d50888391
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# Remove this line to create a well-formed Fossil manifest.
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@@ -1 +1 @@
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f845ede54c065ebd222f3f3488f655f2cbbf2c40bae782b3f4eac76cbb0525ad
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d3dfaeb8b901d290c14b46c9e2970cc6a17a7bba2637bfdd353f49bcf41bd0dc
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191
src/util.c
191
src/util.c
@@ -1620,171 +1620,44 @@ int sqlite3PutVarint(unsigned char *p, u64 v){
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return putVarint64(p,v);
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}
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/*
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** Bitmasks used by sqlite3GetVarint(). These precomputed constants
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** are defined here rather than simply putting the constant expressions
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** inline in order to work around bugs in the RVT compiler.
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**
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** SLOT_2_0 A mask for (0x7f<<14) | 0x7f
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**
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** SLOT_4_2_0 A mask for (0x7f<<28) | SLOT_2_0
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*/
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#define SLOT_2_0 0x001fc07f
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#define SLOT_4_2_0 0xf01fc07f
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/*
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** Read a 64-bit variable-length integer from memory starting at p[0].
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** Return the number of bytes read. The value is stored in *v.
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*/
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u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
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u32 a,b,s;
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if( ((signed char*)p)[0]>=0 ){
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*v = *p;
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return 1;
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u64 iKey = p[0];
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const u8 *pStart = p;
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if( iKey>=0x80 ){
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u8 x;
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iKey = (iKey<<7) ^ (x = *++p);
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if( x>=0x80 ){
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iKey = (iKey<<7) ^ (x = *++p);
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if( x>=0x80 ){
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iKey = (iKey<<7) ^ 0x10204000 ^ (x = *++p);
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if( x>=0x80 ){
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iKey = (iKey<<7) ^ 0x4000 ^ (x = *++p);
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if( x>=0x80 ){
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iKey = (iKey<<7) ^ 0x4000 ^ (x = *++p);
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if( x>=0x80 ){
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iKey = (iKey<<7) ^ 0x4000 ^ (x = *++p);
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if( x>=0x80 ){
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iKey = (iKey<<7) ^ 0x4000 ^ (x = *++p);
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if( x>=0x80 ){
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iKey = (iKey<<8) ^ 0x8000 ^ (*++p);
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}
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}
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}
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}
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}
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}else{
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iKey ^= 0x204000;
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}
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}else{
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iKey ^= 0x4000;
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}
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}
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if( ((signed char*)p)[1]>=0 ){
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*v = ((u32)(p[0]&0x7f)<<7) | p[1];
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return 2;
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}
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/* Verify that constants are precomputed correctly */
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assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
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assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
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a = ((u32)p[0])<<14;
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b = p[1];
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p += 2;
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a |= *p;
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/* a: p0<<14 | p2 (unmasked) */
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if (!(a&0x80))
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{
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a &= SLOT_2_0;
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b &= 0x7f;
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b = b<<7;
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a |= b;
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*v = a;
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return 3;
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}
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/* CSE1 from below */
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a &= SLOT_2_0;
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p++;
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b = b<<14;
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b |= *p;
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/* b: p1<<14 | p3 (unmasked) */
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if (!(b&0x80))
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{
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b &= SLOT_2_0;
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/* moved CSE1 up */
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/* a &= (0x7f<<14)|(0x7f); */
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a = a<<7;
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a |= b;
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*v = a;
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return 4;
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}
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/* a: p0<<14 | p2 (masked) */
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/* b: p1<<14 | p3 (unmasked) */
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/* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
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/* moved CSE1 up */
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/* a &= (0x7f<<14)|(0x7f); */
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b &= SLOT_2_0;
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s = a;
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/* s: p0<<14 | p2 (masked) */
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p++;
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a = a<<14;
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a |= *p;
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/* a: p0<<28 | p2<<14 | p4 (unmasked) */
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if (!(a&0x80))
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{
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/* we can skip these cause they were (effectively) done above
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** while calculating s */
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/* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
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/* b &= (0x7f<<14)|(0x7f); */
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b = b<<7;
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a |= b;
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s = s>>18;
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*v = ((u64)s)<<32 | a;
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return 5;
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}
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/* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
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s = s<<7;
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s |= b;
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/* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
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p++;
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b = b<<14;
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b |= *p;
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/* b: p1<<28 | p3<<14 | p5 (unmasked) */
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if (!(b&0x80))
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{
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/* we can skip this cause it was (effectively) done above in calc'ing s */
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/* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
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a &= SLOT_2_0;
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a = a<<7;
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a |= b;
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s = s>>18;
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*v = ((u64)s)<<32 | a;
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return 6;
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}
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p++;
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a = a<<14;
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a |= *p;
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/* a: p2<<28 | p4<<14 | p6 (unmasked) */
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if (!(a&0x80))
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{
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a &= SLOT_4_2_0;
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b &= SLOT_2_0;
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b = b<<7;
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a |= b;
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s = s>>11;
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*v = ((u64)s)<<32 | a;
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return 7;
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}
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/* CSE2 from below */
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a &= SLOT_2_0;
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p++;
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b = b<<14;
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b |= *p;
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/* b: p3<<28 | p5<<14 | p7 (unmasked) */
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if (!(b&0x80))
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{
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b &= SLOT_4_2_0;
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/* moved CSE2 up */
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/* a &= (0x7f<<14)|(0x7f); */
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a = a<<7;
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a |= b;
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s = s>>4;
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*v = ((u64)s)<<32 | a;
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return 8;
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}
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p++;
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a = a<<15;
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a |= *p;
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/* a: p4<<29 | p6<<15 | p8 (unmasked) */
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/* moved CSE2 up */
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/* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
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b &= SLOT_2_0;
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b = b<<8;
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a |= b;
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s = s<<4;
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b = p[-4];
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b &= 0x7f;
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b = b>>3;
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s |= b;
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*v = ((u64)s)<<32 | a;
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return 9;
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*v = iKey;
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return (u8)(p - pStart) + 1;
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}
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/*
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