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Improvements to opcode documentation in the bytecode engine.

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FossilOrigin-Name: e54c9f8db5b2fa8ea82c6eab7482255431af16901f7992c9667b56a0e50a9f4f
This commit is contained in:
drh
2017-04-29 18:02:49 +00:00
parent bc43995f99
commit bb6783b86f
3 changed files with 28 additions and 29 deletions
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42
src/vdbe.c
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@@ -764,7 +764,7 @@ jump_to_p2_and_check_for_interrupt:
pOp = &aOp[pOp->p2 - 1];
/* Opcodes that are used as the bottom of a loop (OP_Next, OP_Prev,
** OP_VNext, OP_RowSetNext, or OP_SorterNext) all jump here upon
** OP_VNext, or OP_SorterNext) all jump here upon
** completion. Check to see if sqlite3_interrupt() has been called
** or if the progress callback needs to be invoked.
**
@@ -1567,7 +1567,7 @@ arithmetic_result_is_null:
/* Opcode: CollSeq P1 * * P4
**
** P4 is a pointer to a CollSeq struct. If the next call to a user function
** P4 is a pointer to a CollSeq object. If the next call to a user function
** or aggregate calls sqlite3GetFuncCollSeq(), this collation sequence will
** be returned. This is used by the built-in min(), max() and nullif()
** functions.
@@ -1848,11 +1848,11 @@ case OP_RealAffinity: { /* in1 */
** Force the value in register P1 to be the type defined by P2.
**
** <ul>
** <li value="97"> TEXT
** <li value="98"> BLOB
** <li value="99"> NUMERIC
** <li value="100"> INTEGER
** <li value="101"> REAL
** <li> P2=='A' &rarr; BLOB
** <li> P2=='B' &rarr; TEXT
** <li> P2=='C' &rarr; NUMERIC
** <li> P2=='D' &rarr; INTEGER
** <li> P2=='E' &rarr; REAL
** </ul>
**
** A NULL value is not changed by this routine. It remains NULL.
@@ -2723,8 +2723,8 @@ op_column_out:
**
** Apply affinities to a range of P2 registers starting with P1.
**
** P4 is a string that is P2 characters long. The nth character of the
** string indicates the column affinity that should be used for the nth
** P4 is a string that is P2 characters long. The N-th character of the
** string indicates the column affinity that should be used for the N-th
** memory cell in the range.
*/
case OP_Affinity: {
@@ -2751,8 +2751,8 @@ case OP_Affinity: {
** use as a data record in a database table or as a key
** in an index. The OP_Column opcode can decode the record later.
**
** P4 may be a string that is P2 characters long. The nth character of the
** string indicates the column affinity that should be used for the nth
** P4 may be a string that is P2 characters long. The N-th character of the
** string indicates the column affinity that should be used for the N-th
** field of the index key.
**
** The mapping from character to affinity is given by the SQLITE_AFF_
@@ -5748,7 +5748,7 @@ case OP_IntegrityCk: {
/* Opcode: RowSetAdd P1 P2 * * *
** Synopsis: rowset(P1)=r[P2]
**
** Insert the integer value held by register P2 into a boolean index
** Insert the integer value held by register P2 into a RowSet object
** held in register P1.
**
** An assertion fails if P2 is not an integer.
@@ -5768,8 +5768,9 @@ case OP_RowSetAdd: { /* in1, in2 */
/* Opcode: RowSetRead P1 P2 P3 * *
** Synopsis: r[P3]=rowset(P1)
**
** Extract the smallest value from boolean index P1 and put that value into
** register P3. Or, if boolean index P1 is initially empty, leave P3
** Extract the smallest value from the RowSet object in P1
** and put that value into register P3.
** Or, if RowSet object P1 is initially empty, leave P3
** unchanged and jump to instruction P2.
*/
case OP_RowSetRead: { /* jump, in1, out3 */
@@ -5800,15 +5801,14 @@ case OP_RowSetRead: { /* jump, in1, out3 */
** integer in P3 into the RowSet and continue on to the
** next opcode.
**
** The RowSet object is optimized for the case where successive sets
** of integers, where each set contains no duplicates. Each set
** of values is identified by a unique P4 value. The first set
** must have P4==0, the final set P4=-1. P4 must be either -1 or
** non-negative. For non-negative values of P4 only the lower 4
** bits are significant.
** The RowSet object is optimized for the case where sets of integers
** are inserted in distinct phases, which each set contains no duplicates.
** Each set is identified by a unique P4 value. The first set
** must have P4==0, the final set must have P4==-1, and for all other sets
** must have P4>0.
**
** This allows optimizations: (a) when P4==0 there is no need to test
** the rowset object for P3, as it is guaranteed not to contain it,
** the RowSet object for P3, as it is guaranteed not to contain it,
** (b) when P4==-1 there is no need to insert the value, as it will
** never be tested for, and (c) when a value that is part of set X is
** inserted, there is no need to search to see if the same value was