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(Created page with "{{DISPLAYTITLE:_MEMCOPY}} The _MEMCOPY statement copies a block of bytes from one memory offset to another offset in memory. {{PageSyntax}} : _MEMCOPY {{Parameter|sourceBlock}}, {{Parameter|sourceBlock.OFFSET}}, {{Parameter|sourceBlock.SIZE}} TO {{Parameter|destBlock}}, {{Parameter|destBlock.OFFSET}} {{Parameters}} * {{Parameter|sourceBlock}} is the source memory block name created AS _MEM. * {{Parameter|sourceBlock.OFFSET}} is the dot _OFFSET wi...") |
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{{PageExamples}} | {{PageExamples}} | ||
''Example:'' Swapping data from one [[STRING]] variable to another. Fixed length strings are recommended for speed. | ''Example:'' Swapping data from one [[STRING]] variable to another. Fixed length strings are recommended for speed. | ||
{{CodeStart}} | {{CodeStart}} | ||
{{Cl|DIM}} m {{Cl|AS}} {{Cl|_MEM}} | {{Cl|DIM}} m {{Cl|AS}} {{Cl|_MEM}} | ||
{{Cl|DIM}} n {{Cl|AS}} {{Cl|_MEM}} | {{Cl|DIM}} n {{Cl|AS}} {{Cl|_MEM}} | ||
| Line 41: | Line 41: | ||
b$ = {{Cl|SPACE$}}(10) | b$ = {{Cl|SPACE$}}(10) | ||
{{Cl|_MEMGET}} n, n.OFFSET, b$ | {{Cl|_MEMGET}} n, n.OFFSET, b$ | ||
{{Cl|PRINT}} "out:[" + b$ + "]" | {{Cl|PRINT}} "out:[" + b$ + "]" | ||
{{Cl|_MEMFREE}} m: {{Cl|_MEMFREE}} n 'always clear the memory when done | {{Cl|_MEMFREE}} m: {{Cl|_MEMFREE}} n 'always clear the memory when done | ||
{{CodeEnd}} | {{CodeEnd}} | ||
''Snippet:'' Instead of copying each array element, one at a time in nested [[FOR...NEXT|FOR]] loops, _MEMCOPY does it in one statement instantly. | ''Snippet:'' Instead of copying each array element, one at a time in nested [[FOR...NEXT|FOR]] loops, _MEMCOPY does it in one statement instantly. | ||
{{TextStart}} | {{TextStart}} | ||
'copy array a to array b one index at a time: | 'copy array a to array b one index at a time: | ||
{{Cb|FOR...NEXT|FOR}} i1 = 0 {{Cb|TO}} 100 | {{Cb|FOR...NEXT|FOR}} i1 = 0 {{Cb|TO}} 100 | ||
| Line 59: | Line 59: | ||
{{Cb|DIM}} mb {{Cl|AS}} {{Cb|_MEM}}: mb = {{Cb|_MEM (function)|_MEM}}(b()) | {{Cb|DIM}} mb {{Cl|AS}} {{Cb|_MEM}}: mb = {{Cb|_MEM (function)|_MEM}}(b()) | ||
{{Cb|_MEMCOPY}} ma, ma.OFFSET, ma.SIZE {{Cb|TO}} mb, mb.OFFSET | {{Cb|_MEMCOPY}} ma, ma.OFFSET, ma.SIZE {{Cb|TO}} mb, mb.OFFSET | ||
{{Cb|_MEMFREE}} ma: {{Cb|_MEMFREE}} mb 'clear the memory when done | {{Cb|_MEMFREE}} ma: {{Cb|_MEMFREE}} mb 'clear the memory when done | ||
{{TextEnd}} | {{TextEnd}} | ||
Revision as of 02:03, 23 January 2023
The _MEMCOPY statement copies a block of bytes from one memory offset to another offset in memory.
Syntax
- sourceBlock is the source memory block name created AS _MEM.
- sourceBlock.OFFSET is the dot _OFFSET within the source memory block to read from.
- sourceBlock.SIZE is the total number of bytes to transfer based on actual size.
- destBlock is the destination _MEM memory block name to transfer data to.
- destBlock.OFFSET is the dot _OFFSET within the dest _MEM memory block to write to.
Description
- The dot OFFSET is the memory block's start location in memory. Add bytes to place data further into the block.
- The dot SIZE is the total byte size of the memory block to transfer. You can transfer all or a portion of the data bytes.
- The memory block regions may overlap.
- Always free memory blocks after values have been transferred to variables and are no longer required.
Examples
Example: Swapping data from one STRING variable to another. Fixed length strings are recommended for speed.
DIM m AS _MEM DIM n AS _MEM m = _MEMNEW(10) n = _MEMNEW(100) _MEMPUT m, m.OFFSET, "1234567890" s$ = SPACE$(10) 'to load into a variable length string set its length first _MEMGET m, m.OFFSET, s$ PRINT "in:[" + s$ + "]" _MEMCOPY m, m.OFFSET, m.SIZE TO n, n.OFFSET 'put m into n b$ = SPACE$(10) _MEMGET n, n.OFFSET, b$ PRINT "out:[" + b$ + "]" _MEMFREE m: _MEMFREE n 'always clear the memory when done |
Snippet: Instead of copying each array element, one at a time in nested FOR loops, _MEMCOPY does it in one statement instantly.
'copy array a to array b one index at a time: FOR i1 = 0 TO 100 FOR i2 = 0 TO 100 b(i1, i2) = a(i1, i2) NEXT NEXT 'copy array a to array b in memory instantly: DIM ma AS _MEM: ma = _MEM(a()) 'place array data into blocks DIM mb AS _MEM: mb = _MEM(b()) _MEMCOPY ma, ma.OFFSET, ma.SIZE TO mb, mb.OFFSET _MEMFREE ma: _MEMFREE mb 'clear the memory when done |
See also
- _MEM, _MEM (function)
- _MEMNEW, _MEMGET (function)
- _MEMIMAGE, _MEMELEMENT
- _MEMGET, _MEMPUT
- _MEMFILL, _MEMFREE