RemV (changes)
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Programmer's Reference Manuals
» Vectors
» Software Vector Numbers
» RemV
Remove Vector (21)
Byte Removal (option 1)
| Entry | |
|---|---|
| R1 | Buffer number plus flags: |
| b31 clear for Single Removal, set for Block Mode | |
| b30 used by the DeepKeys extension |
| Entry | |
|---|---|
| R1 | Buffer number, bit-31 clear for byte operation |
| R9 | 21 (&15) vector number |
| V flag is set if buffer to be examined only, or 0 if data should be removed | |
Single Removal (R1b31 clear)
| Byte removed (remove option), or corrupted (examine operation) | |
| C flag set if buffer was empty on entry | |
Block Removal (option 2)
| Exit | |
|---|---|
| R0 | Next value to be removed (examine option), or “corrupted” (remove option) |
| R1 | Preserved |
| R2 | Value removed (remove option), or “corrupted” (examine operation) |
| C flag set if buffer was empty on entry | |
| Entry | |
|---|---|
| R1 | Buffer number, bit-31 set for block operation |
| R2 | Pointer to block to be filled |
| R3 | Number of bytes to place into block |
| R9 | 21 (&15) vector number |
| V flag is set if buffer to be examined only, or 0 if data should be removed | |
To work around historical keyboard handling bugs, the Kernel always returns the same value in R0 and R2 for its buffers if C is clear. BufferManager does not match this sensible behaviour.
Block Mode (R1b31 set)
| Entry | |
|---|---|
| R1 | Buffer number, b31 set |
| R2 | Pointer to block to be filled |
| R3 | Number of bytes to place into block |
| R9 | 21 (&15) vector number |
| V flag is set if buffer to be examined only, or 0 if data should be removed | |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
| R2 | Pointer to updated buffer position |
| R3 | Number of bytes still be to be removed |
| C flag set if buffer was empty on entry | |
Use
This vector is called to remove one or more bytes from a buffer.
Notes
All characters removed from buffers are sent through this vector. Used byOS_Byte 145 and OS_Byte 152.
If called via OS_CallAVector then interrupts must be disabled first.
Note that Block Mode is not supported for all buffer numbers. BufferManager does support it for the buffers it manages (Serial, Printer, Mouse).
See also
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