Routines
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DD35: Describe Object If Present
Used by the routine at ReadScheduleEntryFromCurrentCharacter.
Returns zero when A is zero, or when a bit of 28 is set in the object's attribute and its location is not below IY+02. Any other object returns non-zero.
DescribeObjectIfPresent DD35 AND A Return if the object is zero.
DD36 RET Z
DD37 PUSH IX Call FetchObjectDataPointer to look up that object.
DD39 CALL FetchObjectDataPointer
DD3C LD A,(IX+$05) Read the object attribute.
None of the bits 28 are set in the object attribute?
DD3F AND $28 Jump to DescribeObjectIfPresent_Next if none of the bits 28 are set in the object attribute.
DD41 LD A,(IX+$02)
DD44 POP IX
DD46 JR Z,DescribeObjectIfPresent_Next
DD48 CP (IY+$02) Go to DescribeObjectIfPresent_Next if the object's location is below the byte at IY+02.
DD4B JR C,DescribeObjectIfPresent_Next
DD4D XOR A Clear A.
DD4E RET Return.
DescribeObjectIfPresent_Next DD4F OR %00000001 Reset the zero flag.
DD51 RET Return.
Named from the script commands at E460 and E7BE.
DD52 DEFB $A4,$00 Display record read by ProcessDisplayRecord: flags A4 value 00.
DD54 DEFB $17,$61,$DD,$FD,$FF,$60,$DD Refresh the room from the text at DD61, using the low byte of the location, FF and otherwise continue at DD60.
DD5B DEFB $11,$FD,$60,$DD Perform the simple action for the low byte of the location and otherwise continue at DD60.
DD5F DEFB $0B Run the nested character script.
DD60 DEFB $0A Run the nested character script.
DD61 DEFB $64,$00,$6E,$DD Display record read by ProcessDisplayRecord: flags 64 value 00 handler DD6E.
Run by CA64 after the display record at DD61.
DD65 LD A,(IX+$00) Read the object's first byte and store it as the location value.
DD68 LD ($9FD7),A
DD6B OR %00000001 Reset the zero flag.
DD6D RET Return.
Reached through the display record at DD61, dispatched by DispatchLookedUpHandlerThird.
DD6E LD A,($A034) Read the room display parameter and call FindObjectByFieldTwo to find an object by field two.
DD71 CALL FindObjectByFieldTwo
DD74 CP $FF Go to ParseInputNumber_ReturnZero if it is FF.
DD76 JP Z,ParseInputNumber_ReturnZero
DD79 LD A,(IX+$00) Return zero through ParseInputNumber_ReturnZero if the record's flag byte is at least 0B.
DD7C CP $0B
DD7E JP NC,ParseInputNumber_ReturnZero
DD81 OR %00000001 Reset the zero flag.
DD83 RET Return.
Named from the script commands at E476 and E7CF.
DD84 DEFB $6D,$00,$91,$DD Display record read by ProcessDisplayRecord: flags 6D value 00 handler DD91.
Run by CA64 after the display record at DD84.
DD88 LD A,(IX+$01) Record the current room.
DD8B LD ($9FD6),A
DD8E OR %00000001 Reset the zero flag.
DD90 RET Return.
DD91 LD IX,($A013) Read the current object.
DD95 LD A,(IX+$01) Go to ParseInputNumber_ReturnZero if the moved marker is FF.
DD98 AND A
DD99 INC A
DD9A JP Z,ParseInputNumber_ReturnZero
DD9D RET Return.
DD9E DEFB $0D,$10 Display record read by ProcessDisplayRecord: flags 0D value 10.
Run by CA64 after the display record at DD9E.
DDA0 LD A,($A034) Read the room display parameter.
DDA3 CALL FindCharacter Call FindCharacter to find the character.
Was this character FF?
DDA6 CP $FF Use zero and go to DescribeObjectIfPresent_0 if this character is FF.
DDA8 LD A,$00
DDAA JR Z,DescribeObjectIfPresent_0
DDAC LD A,$01 Take 01.
DescribeObjectIfPresent_0 DDAE CALL FollowLinkPointer Call FollowLinkPointer.
DDB1 OR $01
DDB3 RET Return.
DDB4 DEFB $40,$50,$B8,$DD Display record read by ProcessDisplayRecord: flags 40 value 50 handler DDB8.
Reached through the display record at CopySavedCharacterIdentifier, DDB4 and DDD0, dispatched by DispatchLookedUpHandlerThird.
Run by CA64 after the display record at DDB4.
DDB8 CALL CheckFlagAndJumpToNewline Call CheckFlagAndJumpToNewline.
DDBB OR $01
DDBD RET Return.
Named from the script commands at EEBE, EEE4, EF04, EF54, EF75, F0E9, F22D, F246, F25B, F268, F278, F28D and F2AC.
DDBE DEFB $40,$00,$B8,$DD Display record read by ProcessDisplayRecord: flags 40 value 00 handler DDB8.
Run by CA64 after the display record at DDBE.
DDC2 LD A,($A034) Store the room display parameter in the character script cycle.
DDC5 LD ($A01F),A
DDC8 OR %00000001 Reset the zero flag.
DDCA RET Return.
DDCB DEFW $0000 The location text pointer, read by DescribeObjectIfPresent and MeasureGapBetweenTwoPointers_Next.
DDCD DEFW $0000 The object's description pointer, read by DescribeObjectIfPresent and MeasureGapBetweenTwoPointers_Next.
DDCF DEFB $00 Data bytes 00 read by DescribeObjectIfPresent.
DDD0 DEFB $45,$00,$B8,$DD Display record read by ProcessDisplayRecord: flags 45 value 00 handler DDB8.
Run by CA64 after the display record at DDD0.
DDD4 LD HL,($A02F) Read the display pointer.
DDD7 RES 7,H Clear the marker.
DDD9 PUSH HL
DDDA LD A,H
DescribeObjectIfPresent_MaskName DDDB AND $3F Keep the low six bits of the name, then call ScaleHighByteBySixty to scale the high byte by sixty.
DDDD LD H,A
DDDE LD A,L
DDDF AND $3F
DDE1 LD L,A
DDE2 CALL ScaleHighByteBySixty
DDE5 LD ($DDCD),HL Remember the object's description.
DDE8 LD HL,($9FDF) Scale the word at CurrentTime_Minutes by sixty.
DDEB CALL ScaleHighByteBySixty
DDEE LD ($DDCB),HL Remember the location text.
DDF1 POP HL
DDF2 LD A,$61
DDF4 LD ($DDCF),A Store it in the workspace byte at DDCF.
DDF7 BIT 6,H Jump ahead to DescribeObjectIfPresent_ObjectDescriptionLocation if bit 6 is present.
DDF9 JR NZ,DescribeObjectIfPresent_ObjectDescriptionLocation
DDFB LD A,$70 Write the letter p into the description marker.
DDFD LD ($DDCF),A
DE00 BIT 6,L Jump ahead to DescribeObjectIfPresent_ObjectDescriptionLocation if bit 6 is present.
DE02 JR NZ,DescribeObjectIfPresent_ObjectDescriptionLocation
DE04 CALL MeasureGapBetweenTwoPointers_Next Call MeasureGapBetweenTwoPointers_Next, read the AM/PM letter at Messaging_AM_PM and go to DescribeObjectIfPresent_Letter if the description pointer is below the location text.
DE07 LD A,($9FE2)
DE0A JR C,DescribeObjectIfPresent_Letter
DE0C JR NZ,DescribeObjectIfPresent_WorkspaceByte Go to DescribeObjectIfPresent_WorkspaceByte if the description is past the location text.
Is the marker the letter a?
DescribeObjectIfPresent_Letter DE0E CP $61 Use the letter p when the marker is the letter a.
DE10 LD A,$70
DE12 JR Z,DescribeObjectIfPresent_WorkspaceByte
DE14 LD A,$61 Take the letter a.
DescribeObjectIfPresent_WorkspaceByte DE16 LD ($DDCF),A Store it in the workspace byte at DDCF.
DescribeObjectIfPresent_ObjectDescriptionLocation DE19 LD HL,($DDCD) Read the object's description and the location text.
DE1C LD DE,($DDCB)
DE20 AND A Subtract the value at DDCB from the one at DDCD and take 02D0, the half-day step added at DE39.
DE21 SBC HL,DE
DE23 LD DE,$02D0
DE26 LD A,($9FE2) Read the AM/PM marker into C and the description marker at DDCF into B.
DE29 LD C,A
DE2A LD A,($DDCF)
DE2D LD B,A
DE2E CALL MeasureGapBetweenTwoPointers_Next Jump to DescribeObjectIfPresent_AdvancePointerSource if the object's description pointer is below the location text pointer.
DE31 JR C,DescribeObjectIfPresent_AdvancePointerSource
DE33 JR Z,DescribeObjectIfPresent_AdvancePointerSource Go to DescribeObjectIfPresent_AdvancePointerSource if the object's description pointer equals the location text pointer.
DE35 LD A,B Go to DescribeObjectIfPresent_RecordCharacterScript if the description marker matches AM/PM.
DE36 CP C
DE37 JR Z,DescribeObjectIfPresent_RecordCharacterScript
DE39 ADD HL,DE The hours differ, so add one step and store the total from DescribeObjectIfPresent_RecordCharacterScript.
DE3A JR DescribeObjectIfPresent_RecordCharacterScript
Add one step, and a second step when the description marker matches.
DescribeObjectIfPresent_AdvancePointerSource DE3C ADD HL,DE Add one step, and go to DescribeObjectIfPresent_RecordCharacterScript if the description marker does not match AM/PM.
DE3D LD A,B
DE3E CP C
DE3F JR NZ,DescribeObjectIfPresent_RecordCharacterScript
DE41 ADD HL,DE Add one more step to the cycle count.
DescribeObjectIfPresent_RecordCharacterScript DE42 LD ($A01F),HL Record the character script cycle.
DE45 OR %00000001 Reset the zero flag.
DE47 RET Return.
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