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