Routines
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A95B: Process Format Data Byte
Used by the routines at ExtractTokenFromText and ProcessTextTokenFormat.
Input
HL Pointer to format data byte
Output
A Result value
F Zero flag set if end of format reached
ProcessFormatDataByte A95B PUSH BC Stash BC on the stack.
A95C LD IX,$5C42 IX=NEWPPC (load the buffer pointer).
Read and process the format data byte.
A960 INC HL Increment HL by one (move to the format data byte).
A961 LD A,(HL) A=*HL (load the format data byte).
A962 BIT 7,A Test bit 7 of A (check if this is a command byte).
A964 INC HL Increment HL by one (move to the parameter byte).
A965 JR Z,ProcessFormatDataByte_ProcessBits Jump to ProcessFormatDataByte_ProcessBits if bit 7 is not set (data byte, not command).
A967 INC HL Increment HL by two (skip the parameter bytes for command formats).
A968 INC HL
ProcessFormatDataByte_ProcessBits A969 PUSH AF Stash AF (the bit 7 test result) on the stack.
A96A AND %01110000 Keep only bits 4-6 (extract the format command type).
A96C JR Z,ProcessFormatDataByte_ProcessLowNibble Jump to ProcessFormatDataByte_ProcessLowNibble if the command type is zero (simple format).
Adjust the buffer pointer based on the command type.
ProcessFormatDataByte_AdjustBuffer A96E INC IX Increment IX by one (move to the next buffer position).
A970 SUB $10 A-=10 (decrease the command type value).
A972 JR NZ,ProcessFormatDataByte_AdjustBuffer Jump to ProcessFormatDataByte_AdjustBuffer if we need to skip more positions.
ProcessFormatDataByte_ProcessLowNibble A974 LD C,$00 C=00 (initialise the result counter).
A976 POP AF Restore AF (the bit 7 test result) from the stack.
A977 AND %00001111 Keep only bits 0-3 (extract the low nibble).
A979 JR Z,ProcessFormatDataByte_End Jump to ProcessFormatDataByte_End if there's nothing to process.
ProcessFormatDataByte_ProcessLoop A97B LD B,A B=A (store the count in B).
ProcessFormatDataByte_ProcessCommand A97C CALL RotateAndExtractCharacterCode Call RotateAndExtractCharacterCode to process the format command.
A97F LD (IX+$00),A Write A (the processed value) to *IX+00.
A982 INC IX Increment IX by one (move to the next buffer position).
A984 DJNZ ProcessFormatDataByte_ProcessCommand Decrease counter by one and loop back to ProcessFormatDataByte_ProcessCommand until counter is zero.
ProcessFormatDataByte_End A986 LD (IX+$00),$00 Write 00 (terminator) to *IX+00.
A98A LD A,C A=C (load the result counter).
A98B POP BC Restore BC from the stack.
A98C AND A Return if the result counter is zero.
A98D RET Z
A98E INC HL Increment HL by one (move to the next format byte).
A98F RET Return.
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