Routines |
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Used by the routine at SAVE_ETC.
The verification process involves the loading of a block of data, a byte at a time, but the bytes are not stored - only checked. This routine is also used to load blocks of data that have been described with 'SCREEN$' or 'CODE'.
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VR_CONTRL | 01995 | PUSH HL | Save the 'pointer'. | |||||
01996 | LD L,(IX-6) | Fetch the 'number of bytes' as described in the 'old' header. | ||||||
01999 | LD H,(IX-5) | |||||||
02002 | LD E,(IX+11) | Fetch also the number from the 'new' header. | ||||||
02005 | LD D,(IX+12) | |||||||
02008 | LD A,H | Jump forward if the 'length' is unspecified, e.g. 'LOAD name CODE' only. | ||||||
02009 | OR L | |||||||
02010 | JR Z,VR_CONT_1 | |||||||
02012 | SBC HL,DE | Give report R if attempting to load a larger block than has been requested. | ||||||
02014 | JR C,REPORT_R | |||||||
02016 | JR Z,VR_CONT_1 | Accept equal 'lengths'. | ||||||
02018 | LD A,(IX+0) | Also give report R if trying to verify blocks that are of unequal size. ('Old length' greater than 'new length'.) | ||||||
02021 | CP 3 | |||||||
02023 | JR NZ,REPORT_R | |||||||
The routine continues by considering the 'destination pointer'.
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VR_CONT_1 | 02025 | POP HL | Fetch the 'pointer', i.e. the 'start'. | |||||
02026 | LD A,H | This 'pointer' will be used unless it is zero, in which case the 'start' found in the 'new' header will be used instead. | ||||||
02027 | OR L | |||||||
02028 | JR NZ,VR_CONT_2 | |||||||
02030 | LD L,(IX+13) | |||||||
02033 | LD H,(IX+14) | |||||||
The verify/load flag is now considered and the actual load made.
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VR_CONT_2 | 02036 | PUSH HL | Move the 'pointer' to the IX register pair. | |||||
02037 | POP IX | |||||||
02039 | LD A,(23668) | Jump forward unless using the VERIFY command (T-ADDR-lo=2), with the carry flag signalling 'LOAD'. | ||||||
02042 | CP 2 | |||||||
02044 | SCF | |||||||
02045 | JR NZ,VR_CONT_3 | |||||||
02047 | AND A | Signal 'VERIFY'. | ||||||
VR_CONT_3 | 02048 | LD A,255 | Signal 'accept data block only' before loading the block. | |||||
This routine continues into LD_BLOCK.
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