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Routines |
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Used by the routines at InitialiseCharacterDataStructure, LinkCharacterWhenFlagged, ProcessTextTokenStream, ReadPointerFirstDisplay, RecordResultCharacterScript, DispatchCharacterScript, 52671, AllocateMemoryAndStoreCharacter and StoreResultHighByte.
Grows the workspace at 40931 by the size asked for, plus a three-byte header, and returns the new block.
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| AllocateMemory | 41244 | PUSH IY | Add 3 to the total. | |
| 41246 | PUSH HL | |||
| 41247 | PUSH DE | |||
| 41248 | PUSH BC | |||
| 41249 | ADD A,3 | |||
| 41251 | LD C,A | |||
| 41252 | LD B,0 | Start the free-space search and read the list at 40931. | ||
| 41254 | LD HL,(40931) | |||
| 41257 | LD IY,40931 | Point IY at the free-space list (40931). | ||
| AllocateMemory_Loop | 41261 | LD A,L | Jump ahead to AllocateMemory_TestBitCountLink if the pointer is 0000. | |
| 41262 | OR H | |||
| 41263 | JR Z,AllocateMemory_TestBitCountLink | |||
| 41265 | LD E,(HL) | Jump ahead to AllocateMemory_Next when the high byte of this free block is set. | ||
| 41266 | INC HL | |||
| 41267 | LD D,(HL) | |||
| 41268 | INC HL | |||
| 41269 | LD A,D | |||
| 41270 | AND A | |||
| 41271 | JR NZ,AllocateMemory_Next | |||
| 41273 | LD A,E | Jump ahead to AllocateMemory_NextBlock if the first value is below the second. | ||
| 41274 | CP C | |||
| 41275 | JR C,AllocateMemory_NextBlock | |||
| AllocateMemory_Next | 41277 | BIT 0,B | Jump ahead to AllocateMemory_KeepAllocationRemember if bit 0 is clear. | |
| 41279 | JR Z,AllocateMemory_KeepAllocationRemember | |||
| 41281 | PUSH HL | Read the pointer saved ahead of this record. | ||
| 41282 | LD L,(IX-2) | |||
| 41285 | LD H,(IX-1) | |||
| 41288 | AND A | Compare HL with DE. | ||
| 41289 | SBC HL,DE | |||
| 41291 | POP HL | Restore HL from the stack. | ||
| 41292 | JR C,AllocateMemory_NextBlock | Jump ahead to AllocateMemory_NextBlock if HL was below DE. | ||
| AllocateMemory_KeepAllocationRemember | 41294 | PUSH HL | Copy the allocation into IX and remember the caller's index. | |
| 41295 | POP IX | |||
| 41297 | LD (41242),IY | |||
| 41301 | SET 0,B | Set the mark on this character. | ||
| AllocateMemory_NextBlock | 41303 | PUSH HL | Follow the next free block and repeat from AllocateMemory_Loop. | |
| 41304 | POP IY | |||
| 41306 | LD E,(HL) | |||
| 41307 | INC HL | |||
| 41308 | LD D,(HL) | |||
| 41309 | EX DE,HL | |||
| 41310 | JR AllocateMemory_Loop | |||
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See whether bit 0 of the count is set, then read the link stored ahead of this record, then clear the high byte of the count.
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| AllocateMemory_TestBitCountLink | 41312 | BIT 0,B | Jump ahead to StoreThatByteLinkAhead_JoinStep if bit 0 is clear. | |
| 41314 | JR Z,StoreThatByteLinkAhead_JoinStep | |||
| 41316 | LD L,(IX-2) | Read the pointer saved ahead of this record and count 0. | ||
| 41319 | LD H,(IX-1) | |||
| 41322 | LD B,0 | |||
| 41324 | AND A | Clear the carry before subtracting the block length from the free space. | ||
| 41325 | SBC HL,BC | Measure the pointer against the count. | ||
| 41327 | LD A,H | Read the high byte of the pointer. | ||
| 41328 | AND A | Clear the carry so a zero high byte means only a few bytes of free space remain. | ||
| 41329 | JR NZ,StoreThatByteLinkAhead | Jump to StoreThatByteLinkAhead when the free space still has a high byte. | ||
| 41331 | LD A,L | Go to StoreThatByteLinkAhead if at least four bytes of free space remain. | ||
| 41332 | CP 4 | |||
| 41334 | JR NC,StoreThatByteLinkAhead | |||
| 41336 | LD IY,(41242) | Bring the saved index back from 41242 and read the character id. | ||
| 41340 | LD A,(IX+0) | |||
| 41343 | LD (IY+0),A | Store the character id. | ||
| 41346 | LD A,(IX+1) | Jump ahead to StoreThatByteLinkAhead_TestBytePreviousMemory to step to the next character record. | ||
| 41349 | LD (IY+1),A | |||
| 41352 | JR StoreThatByteLinkAhead_TestBytePreviousMemory | |||
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