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Text File | 2006-10-19 | 15.6 KB | 615 lines

* I/O Opcode 3 - WRITE * * This routine will store a record into the file buffer providing * the file has been open for writing. If the buffer is full, it * will call FLUSH to write it out to disk and then start a new * buffer. * WRITE0 ANDI R12,>FF00 AI R12,24 LDCR @B02,4 Select RAM bank 2 BLWP @IFO See if file is open JEQ WRITE2 WRITE1 BL @DSRERR DATA >0700 File error * If the file is open for input mode, error. All other modes * allow write access. WRITE2 CB @56(R5),@B02 Input mode JNE WRITE3 BL @DSRERR DATA >0200 Bad open attribute? * Now check to see if we're doing sequential or random I/O WRITE3 LDCR @ZERO,4 MOVB @PABBUF+1,R1 ANDI R1,>0100 JEQ WRITE4 * We're handling relative I/O now! 7-2-95 B @WRIT50 * The first thing we do is see if we're working on an AU. If * not, we assume this is the first record being written to this * file. If the data chain is empty, we allocate an AU for it. * Otherwise, we use the AU that's already allocated. WRITE4 LDCR @B02,4 Select RAM bank 2 C @50(R5),@ZERO See if current AU=0 JEQ WRT4Z B @WRIT10 WRT4Z * Let's see if this file has any AU's allocated for it already. * MOV @4(R5),R1 Get FDR address LDCR @2(R5),4 Select bank with FDR MOV @40(R1),R7 Get 1st AU in chain JEQ WRIT4A LDCR @B02,4 MOV R7,@50(R5) Save the AU * If we're in update mode and the file has fixed length records, * we should read in the data to the buffer. CB @ZERO,@56(R5) See if update mode JNE WRIT6B LDCR @2(R5),4 MOVB @12(R1),R0 Get file flags ANDI R0,8000 JNE WRIT6B LDCR @B04,4 We have to read it in! MOV R6,R3 SRL R3,8 SLA R3,1 MPY @SAUTBL(R3),R7 LI R3,SECBUF SRL R8,1 JNC WRT4A AI R3,>100 WRT4A SRL R7,1 JNC WRT4B AI R8,>8000 WRT4B LDCR @ZERO,4 BLWP @BANKIT DATA SCSIRD JEQ WRT4C BL @DSRERR DATA >0600 Device error WRT4C LDCR @B02,4 MOV @6(R5),R7 Get Buffer address MOVB @3(R5),R8 Get buffer bank WRT4D LDCR @ZERO,4 MOV *R3+,R0 LDCR R8,4 MOV R0,*R7+ CI R3,SECBUF+512 JNE WRT4D JMP WRIT6B * OK. Let's go out and allocate the 1st AU for the file WRIT4A MOV R5,R0 Save pointer to cache entry CLR R7 No preferred starting AU LI R8,1 We want 1 AU LI R3,256*8 AU boundry LDCR @ZERO,4 Select RAM bank 0 BLWP @ALLOC JEQ WRITE5 BL @DSRERR DATA >0600 Device error WRITE5 CI R4,0 Make sure we got one JNE WRITE6 BL @DSRERR DATA >0400 Out of space WRITE6 LDCR @B02,4 Select RAM bank 2 MOV R5,R2 MOV R0,R5 Restore pointer MOV R2,@50(R5) Save current AU * Put the AU in the data chain MOV @4(R5),R1 Get pointer to FDR LDCR @2(R5),4 MOV R2,@40(R1) Store AU in data chain MOV R2,@42(R1) INC @34(R1) Increment # of AU's in FDR LDCR @B04,4 Set # of sectors allocated MOV R6,R3 SRL R3,8 SLA R3,1 MOV @SAUTBL(R3),R3 LDCR @B02,4 LDCR @2(R5),4 MOV R3,@14(R1) WRIT6B LDCR @B02,4 CLR @52(R5) Sector within AU = 0 CLR @58(R5) Buffer size = 256 MOV @6(R5),@54(R5) Pointer within buffer LDCR @2(R5),4 Select bank with FDR MOVB @12(R1),R3 If variable length records, ANDI R3,>8000 Set sector # to one JEQ WRT6A LI R3,1 LDCR @B02,4 MOV R3,@62(R5) * See if we can use a 512 byte buffer * WRT6A LDCR @B04,4 Select RAM bank 4 MOV R6,R3 SRL R3,8 SLA R3,1 MOV @SAUTBL(R3),R1 CI R1,1 JEQ WRITE8 ANDI R1,>0001 JEQ WRITE7 ANDI R2,>0001 JNE WRITE8 WRITE7 LDCR @B02,4 Select RAM bank 2 SETO @58(R5) WRITE8 B @WRIT30 * Here we check to see if there is enough room in the buffer * to hold the record. In the case of variable length files, * we must also account for the record size byte and the * end of sector marker. * WRIT10 LDCR @B02,4 MOV @4(R5),R1 LDCR @2(R5),4 MOVB @17(R1),R2 Get record size MOVB @12(R1),R4 Get file flags LDCR @ZERO,4 CB @PABBUF+5,R2 Make sure we're not trying JL WRIT11 to write more characters than JEQ WRIT11 the file allows BL @DSRERR DATA >0700 File error WRIT11 SRL R2,8 ANDI R4,>8000 Check for fixed or variable JEQ WRIT12 MOVB @PABBUF+5,R2 Get character count from PAB SRL R2,8 INCT R2 Add in length byte and EOS marker WRIT12 * We will now see if there's enough room in the buffer LDCR @B02,4 Select RAM bank 2 MOV @54(R5),R1 Get pointer within buffer S @6(R5),R1 Subtract the base address CI R1,>200 JEQ WRIT14 CI R1,>100 JNE WRT12A C @58(R5),@ZERO See if buffer size is 256 JEQ WRIT14 If so, read next sector WRT12A MOV @54(R5),R1 ANDI R1,>00FF A R2,R1 CI R1,>100 JH WRIT13 B @WRIT30 * There is not enough room in the buffer to add one more * record. First we check to see if the buffer size is 512 * bytes. If so, we see if we are in the first half and simply * adjust a couple of pointers to go to the second half of * the buffer. Otherwise, we write the buffer out to disk * and start a new one. WRIT13 * If we have variable length records, * we want to increment our sector # LDCR @B02,4 MOV @4(R5),R1 Get address of FDR LDCR @2(R5),4 Select bank with FDR MOV @12(R1),R0 Get file flags LDCR @B02,4 Select Bank 2 again ANDI R0,>8000 JEQ WRT13A INC @62(R5) Increment sector # WRT13A MOV @58(R5),R1 Check for 512 byte buffer JEQ WRIT14 MOV @54(R5),R1 Get pointer in buffer ANDI R1,>0100 Check what half we're in JNE WRIT14 MOV @54(R5),R1 Just go to 2nd half of buffer ANDI R1,>FF00 AI R1,>100 MOV R1,@54(R5) B @WRIT30 * Here we have to write the buffer out to disk. We then * go to the next sector in the AU or next AU. If there * are no more AU's, we have to allocate a new one and * put it at the end of the data chain * * If we are in update mode writing fixed length records, * we read the old data into the buffer. WRIT14 BL @FLUSH LDCR @B04,4 Select RAM bank 4 MOV R6,R3 Get number of sectors / AU SRL R3,8 SLA R3,1 MOV @SAUTBL(R3),R3 LDCR @B02,4 Select RAM bank 2 INC @52(R5) Go to next sector in AU MOV @6(R5),@54(R5) Reset pointer within buffer C @58(R5),@ZERO If buffer size is 512 bytes, JEQ WRIT15 then add another sector INC @52(R5) WRIT15 C @52(R5),R3 See if we need to go to next AU JL WRT18A S R3,@52(R5) * We now have to search the data chain to see where our * AU is. If it's at the end of the file, we have to * allocate a new AU. MOV @50(R5),R2 Get current AU MOV @4(R5),R1 Get FDR address AI R1,42 Point to data chain (+2) LDCR @2(R5),4 WRIT16 C *R1,@ZERO Are we at the end? JEQ WRIT17 C *R1,R2 Is this our AU? JEQ WRIT19 AI R1,4 JMP WRIT16 WRIT17 INC R2 Just go to next AU WRIT18 LDCR @B02,4 MOV R2,@50(R5) CLR @58(R5) Set buffer size to 256 WRT18A * Here we check to see if we're in update mode * and have fixed length records. If so, we want * to read the sector first LDCR @B02,4 CB @ZERO,@56(R5) See if update mode JNE WRT18F LDCR @2(R5),4 MOVB @12(R1),R0 Get file flags ANDI R0,8000 JNE WRT18F LDCR @B04,4 We have to read it in! MOV R6,R3 SRL R3,8 SLA R3,1 MPY @SAUTBL(R3),R7 LI R3,SECBUF SRL R8,1 JNC WRT18B AI R3,>100 WRT18B SRL R7,1 JNC WRT18C AI R8,>8000 WRT18C LDCR @ZERO,4 BLWP @BANKIT DATA SCSIRD JEQ WRT18D BL @DSRERR DATA >0600 Device error WRT18D LDCR @B02,4 MOV @6(R5),R7 Get Buffer address MOVB @3(R5),R8 Get buffer bank WRT18E LDCR @ZERO,4 MOV *R3+,R0 LDCR R8,4 MOV R0,*R7+ CI R3,SECBUF+512 JNE WRT18E WRT18F B @WRIT30 WRIT19 MOV @2(R1),R2 Get next AU JNE WRIT18 * It looks like we have to allocate another AU for the * file. Here we go. MOV R5,R0 Save pointer MOV *R1,R7 Set preferred AU INC R7 LI R8,1 We want 1 AU LI R3,256 In case we don't get the one we want LDCR @ZERO,4 BLWP @ALLOC JEQ WRIT20 BL @DSRERR DATA >0600 Device error WRIT20 CI R4,0 JNE WRIT21 BL @DSRERR DATA >0400 Out of space error WRIT21 MOV R5,R2 Save the AU MOV R0,R5 Restore pointer LDCR @B02,4 MOV @4(R5),R8 Get FDR address LDCR @2(R5),4 INC @34(R8) Increment # of AUs allocated LDCR @B04,4 Set # of sectors allocated MOV R6,R3 SRL R3,8 SLA R3,1 MOV @SAUTBL(R3),R3 LDCR @B02,4 LDCR @2(R5),4 A R3,@14(R8) C R7,R2 Did we get the AU we wanted? JEQ WRIT23 INCT R1 If not, add a new entry to chain MOV R2,*R1+ WRIT23 MOV R2,*R1 LDCR @B02,4 MOV R2,@50(R5) Store current AU CLR @58(R5) Set buffer size to 256 * Now see if we can use a 512 byte buffer B @WRT6A ** * * Here is the infamous WRIT30. Here is where we store the * record in the file buffer and set the buffer modified flag * ** WRIT30 LDCR @ZERO,4 MOVB @PABBUF+3,@VDPWA Set VDP read address to user's buffer NOP MOVB @PABBUF+2,@VDPWA LDCR @B02,4 MOV @54(R5),R1 Get pointer in buffer MOV @4(R5),R2 Get FDR address SETO @60(R5) Set buffer modified flag * If we are doing variable length files, then we have to * put the byte count in first LDCR @2(R5),4 Select bank with FDR MOVB @12(R2),R7 Get file flags ANDI R7,>8000 JEQ WRIT31 LDCR @ZERO,4 MOVB @PABBUF+5,R4 Get character count LDCR @B02,4 LDCR @3(R5),4 MOVB R4,*R1+ JEQ WRIT34 JMP WRIT32 WRIT31 MOVB @17(R2),R4 Get fixed record size from FDR WRIT32 LDCR @B02,4 SRL R4,8 LDCR @3(R5),4 Get buffer bank swapped in WRIT33 MOVB @VDPRD,*R1+ DEC R4 JNE WRIT33 * If we're doing variable length files, put in a new * end of sector marker after the record. CI R7,0 JEQ WRIT36 WRIT34 MOVB @B255,*R1 MOV R1,R7 Set end of file offset SWPB R7 LDCR @B02,4 MOV @62(R5),R8 Get sector number SWPB R8 LDCR @2(R5),4 MOVB R7,@16(R2) Save end of file offset MOV R8,@18(R2) Save # of level 3 records WRIT35 LDCR @B02,4 MOV R1,@54(R5) Save pointer within buffer LDCR @ZERO,4 B @DSRRT * For fixed length files, we need to increment the record # * and if it's greater than the last record written, update * the FDR. WRIT36 LDCR @B02,4 INC @62(R5) Increment the record # MOV @62(R5),R0 MOV @4(R5),R2 Get FDR address LDCR @2(R5),4 Select BANK with FDR MOV @18(R2),R3 Get # of level 3 records written SWPB R3 C R0,R3 JL WRIT35 SWPB R0 MOV R0,@18(R2) Update Level 3 field in FDR JMP WRIT35 ** * * Here is where we handle relative I/O. If we are trying * to write past the end of file, we need to allocate some * more AUs * ** WRIT50 * Step 1: Make sure the file was opened for relative access LDCR @B02,4 Select RAM bank 2 MOVB @57(R5),R0 JNE WRIT51 BL @DSRERR DATA >0700 File error WRIT51 LDCR @ZERO,4 MOV @PABADR,R10 Increment record number in AI R10,6 caller's PAB ORI R10,>4000 SWPB R10 MOVB R10,@VDPWA SWPB R10 MOVB R10,@VDPWA MOV @PABBUF+6,R10 INC R10 MOVB R10,@VDPWD SWPB R10 MOVB R10,@VDPWD MOV @PABBUF+6,R10 Get record # to write LDCR @B02,4 MOV @4(R5),R1 Get FDR address LDCR @2(R5),4 MOV @18(R1),R2 See if we're writing past EOF SWPB R2 C R10,R2 JHE WRIT53 If so, extend the file WRIT52 BL @POSIT B @WRIT30 WRIT53 * Here we're writing past the end of the file. Let's begin * by computing the number of AU's that will be needed. CLR R9 * DEC R10 MOVB @13(R1),R0 Get # of records/sector MOV @34(R1),R2 Get # of AU's allocated SRL R0,8 DIV R0,R9 R9 now has # of sectors needed LDCR @B04,4 MOV R6,R3 SRL R3,8 SLA R3,1 CLR R8 DIV @SAUTBL(R3),R8 R8 now has # of AU's we need INC R8 S R2,R8 Subtract the # of AU's we have WRIT54 CI R8,0 JNE WRIT55 LDCR @B04,4 Get # of sectors / AU MOV R6,R3 SRL R3,8 SLA R3,1 MOV @SAUTBL(R3),R3 LDCR @ZERO,4 MOV @PABBUF+6,R10 Update # of level 3 records LDCR @B02,4 MOV @4(R5),R1 Get FDR address LDCR @2(R5),4 INC R10 SWPB R10 MOV R10,@18(R1) MOV @34(R1),R7 Multiply AU's by secotrs/AU MPY R3,R7 to get # of sectors allocated MOV R8,@14(R1) JMP WRIT52 * Here is where we allocate some more AU's for the file WRIT55 CLR R7 No preferred starting AU LI R3,256 AU boundry LDCR @ZERO,4 MOV R5,R0 Save R5 BLWP @ALLOC JEQ WRIT56 BL @DSRERR DATA >0600 Device error WRIT56 CI R4,0 JNE WRIT57 BL @DSRERR DATA >0400 Out of space WRIT57 MOV R5,R2 Save starting AU MOV R0,R5 Restore R5 * Now put the new AU's in the data chain LDCR @B02,4 MOV @4(R5),R1 Get FDR address LDCR @2(R5),4 A R4,@34(R1) Update # of AU's allocated S R4,R8 Subtract from # needed AI R1,40 Point to data chain WRIT58 C *R1,@ZERO JEQ WRIT59 AI R1,4 JMP WRIT58 WRIT59 DECT R1 MOV *R1,R10 INC R10 C R2,R10 JNE WRIT60 A R4,*R1 JMP WRIT54 WRIT60 INCT R1 MOV R2,*R1+ MOV R2,*R1 A R4,*R1 DEC *R1 JMP WRIT54