New references

Author: intoinside

0000.md

@@ -0,0 +1,74 @@
+---
+layout: default
+title: 0000 - Zero page
+---
+# $0000-$00FF
+
+<a name="AC"></a><a name="AD"></a>
+
+## 172-173 $AC-$AD SAL-SAH
+### Kernal working address pointer
+These locations are used as a pointer to the address of the current
+byte to be written to tape or saved to disk, or the address
+where the byte read from tape or from a disk boot sector is to
+be stored. The Kernal has several routines to service this pointer,
+including:
+
+* [$ED51](E000#ED51) load this pointer with the operation starting address in [$C1-$C2](#C1)
+* [$EEC1](E000#EEC1) increment the address here
+* [$EEB7](E000#EEB7) compare the address here against the operation ending address at [$AE-$AF](#AE)
+
+There is also a routine [$F7CC](E000#F7CC) to retrieve the character at
+the pointer address from the bank specified in [$C6](#C6),
+and one [$F7BC](E000#F7BC) to store the current accumulator contents at
+the pointer address in the bank specified in [$C6](#C6).
+
+<a name="AF"></a>
+
+## 172-175 $AC-$AF
+### Work area for disk booting
+The Kernal BOOT_CALL routine [$F890](E000#F890) uses locations
+$AC-$AD to hold the address at which the contents
+of additional boot sectors are to be stored. Location $AE
+holds the bank number for the additional data. Location $AF
+holds the number of disk sectors to be loaded during the
+boot process.
+
+<a name="AE"></a><a name="AF"></a>
+
+## 174-175 $AE-$AF EAL-E AH
+### Kernal address pointer
+This location is used during the routines which read from or
+write to tape, or in saving to disk, to hold the ending address
+for the operation. For loading from disk, this location is used
+as a working pointer to the address where data is stored. After
+all bytes have been loaded, the locations will hold the ending
+address.
+
+Actually, in all cases the pointer will hold the address
+of the location immediately following the last one involved in the
+operation. The Kernal SAVE routine [$F53E](E000#F53E)
+initializes these locations with the contents of the X and Y registers
+when the routine is called. The Kernal provides a routine
+[$F7C9](E000#F7C9) to retrieve the character at the pointer address from
+the bank specified in [$C6](#C6), and one [$F7BF](E000#F7BF) to store the
+current accumulator contents at the pointer address in the
+bank specified in [$C6](#C6).
+
+<a name="FA"></a>
+
+## 250 $FA Unused
+This memory location is considered unused in that no Commodore 128 Kernal or BASIC routine deliberately changes it. However, due to a bug in the screen editor CINT [$C07B](C000#C07B) and SWAPPER [$CD2E](C000#CD2E) routines, it is overwritten whenever those routines run.
+
+Since these routines are triggered during the RUN/STOP-RESTORE sequence, any value you store here will be lost whenever you press RUN/STOP-RESTORE or switch screens. For this reason, if you use this location in your programs, it should only serve as temporary working space, not for storing important data that you need to keep in the situations mentioned above.
+
+<a name="FB"></a><a name="FE"></a>
+
+## 251-254 $FB-$FE Unused
+These memory locations are not used by any Commodore 128 ROM routines, making them available for your BASIC or machine language programs. They are not affected by the RUN/STOP-RESTORE key combination. However, keep in mind that all zero-page locations, including these, are cleared to zero during a reset—unless the RUN/STOP key is held down while resetting. For more information, refer to the reset routine at [$E000](E000#E000).
+
+<a name="FF"></a>
+
+## 255 $FF
+This location is used as part of the assembly area for character
+strings representing the digits of numeric values.

E000.md

@@ -6,8 +6,26 @@ title: $E000-$FFFF - Kernal Rom, Standard Commodore Jump Table
 
 # Kernal ROM
 
-## 65363 $FF53 JBOOT_CALL <a name="FF53"></a>
-It's an entry point for the Kernal BOOT_CALL routine at $F890 which attempts to load and execute the boot sector from an auto-boot disk in the given drive and device. The BOOT protocol is as follows:
+<a name="F890"></a>
+
+## 63632 $F890 BOOT_CALL
+
+<span class="badge badge-info">Has a jump table entry at [$FF53](#FF53)</span>
+
+<a name="FF53"></a>
+
+## 65363 $FF53 JBOOT_CALL
+
+<span class="badge badge-info">Entry point for the BOOT_CALL routine, currently at [$F890](#F890)</span>
+
+Routine needs parameter to be set:
+
+* .X must hold device number
+* .A must hold the character code corresponding to the desidered drive number (for ex. you should use $30 which corresponds to 0)
+
+If the specified drive is not present or turned off, or the disk does not contain valid boot sectors, the routine will return carry bit set.
+
+BOOT_CALL routine at [$F890](#F890) which attempts to load and execute the boot sector from an auto-boot disk in the given drive and device. The BOOT protocol is as follows:
 
 * Close all open files on boot device.
 * Read track 1 sector 0 into TBUFFR ($B00).
@@ -55,13 +73,13 @@ $0C -> $00                  // no filename
 $0D ->                      // code
   $20, $7D, $FF,            // JSR $FF7D (JPRIMM)
   $0D, $53, $45, $4C, $45,  // String start
-  $43, $54, $20, $4D, $4F, 
-  $44, $45, $3A, $0D, $0D, 
-  $20, $31, $2E, $20, $43, 
-  $36, $34, $20, $20, $42, 
-  $41, $53, $49, $43, $0D, 
-  $20, $32, $2E, $20, $43, 
-  $31, $32, $38, $20, $42, 
+  $43, $54, $20, $4D, $4F,
+  $44, $45, $3A, $0D, $0D,
+  $20, $31, $2E, $20, $43,
+  $36, $34, $20, $20, $42,
+  $41, $53, $49, $43, $0D,
+  $20, $32, $2E, $20, $43,
+  $31, $32, $38, $20, $42,
   $41, $53, $49, $43, $0D,
   $20, $33, $2E, $20, $43,
   $31, $32, $38, $20, $4D,
@@ -74,7 +92,7 @@ $0D ->                      // code
   $EB, $4C, $00, $B0
 </pre>
 
-Starting from $0D, the first three bytes stands for 
+Starting from $0D, the first three bytes stands for
 
 <pre>
 JSR $FF7D