Routines
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AD9E: Restore Item Rows
Used by the routines at RunFrame and RunGame.
Replays the table of item records built by BuildDrawList and PrepareEntityItem. For each record, the rows of the screen buffer saved in the record are copied back to the address in the record header, working upwards one row at a time.
RestoreItemRows AD9E LD A,($F500) Read how many item records there are.
ADA1 AND A Return when there are none.
ADA2 RET Z
The alternate accumulator counts the records. The first byte of a header is the step back to the previous row.
ADA3 LD HL,$F501 Start at the first record.
RestoreItemRows_Loop ADA6 EX AF,AF' Remember how many records remain.
ADA7 LD A,(HL) Patch the step back to the previous row.
ADA8 LD ($ADDE),A
ADAB INC HL Move on to the screen address.
ADAC LD E,(HL) Read the screen address from the header.
ADAD INC HL
ADAE LD D,(HL)
ADAF INC HL
ADB0 LD A,(HL) Patch the row loop with the width.
ADB1 LD ($ADE5),A
ADB4 INC HL Move on to the row count.
ADB5 LD B,(HL) Read how many rows.
ADB6 INC HL
ADB7 LD C,$FF Keep the byte count from carrying into the row count.
ADB9 JP RestoreItemRows_Rows Join the row loop.
RestoreItemRows_Next ADBC EX AF,AF' Repeat for the remaining records.
ADBD DEC A
ADBE JP NZ,RestoreItemRows_Loop
ADC1 RET Return.
Copy three words from the stack. The patched jump cannot reach this for a width of up to six bytes, so it is not used.
RestoreItemRows_Words ADC2 POP DE Copy three words from the stack.
ADC3 LD (HL),E
ADC4 INC HL
ADC5 LD (HL),D
ADC6 INC HL
ADC7 POP DE
ADC8 LD (HL),E
ADC9 INC HL
ADCA LD (HL),D
ADCB INC HL
ADCC POP DE
ADCD LD (HL),E
ADCE INC HL
ADCF LD (HL),D
Copy one byte of the row for each of these that the patched jump reaches. A wider row starts further up the list.
RestoreItemRows_Copy ADD0 LDI Copy a byte and move on.
ADD2 LDI Copy a byte and move on.
ADD4 LDI Copy a byte and move on.
ADD6 LDI Copy a byte and move on.
ADD8 LDI Copy a byte and move on.
ADDA LDI Copy a byte and move on.
Move back one row. The distance subtracted below is patched from the record header.
RestoreItemRows_Step ADDC LD A,E Step back to the previous row.
ADDD SUB $00
ADDF LD E,A
ADE0 JP NC,RestoreItemRows_Rows Stay on this page if the step did not borrow.
ADE3 DEC D Move to the previous page.
RestoreItemRows_Rows ADE4 DJNZ RestoreItemRows_Rows Repeat for the remaining rows. The displacement is patched.
ADE6 JP RestoreItemRows_Next Go on to the next record.
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