The Sidney Affair: Routine at 64265

Copies one frame of the picture held in the buffer at PictureBuffer to the screen: first the pixel rows, then the attributes from PictureBuffer_Attributes. Called by BASIC as "ins" (64265) with the frame number POKEd into DisplayFrame_Number.

The routine works out the frame's row and column in the sheet from *DisplayFrame_Number and *DisplayFrame_PerRow, converts those to byte offsets with DisplayFrame_CalculateOffset, and copies *DisplayFrame_Height character rows of *DisplayFrame_LineWidth bytes from the buffer to the screen at *DisplayFrame_Column / *DisplayFrame_Row. It then copies the matching attributes from the buffer (offset by 6144) to the attribute file.

The values in the snapshot describe rows of 4 frames of 8 by 10 characters, copied to column 25 row 3 after line 60.

Copies one frame of the picture held in the buffer at PictureBuffer to the screen: first the pixel rows, then the attributes from PictureBuffer_Attributes. Called by BASIC as "ins" (64265) with the frame number POKEd into DisplayFrame_Number. The routine works out the frame's row and column in the sheet from DisplayFrame_Number and DisplayFrame_PerRow, converts those to byte offsets with DisplayFrame_CalculateOffset, and copies DisplayFrame_Height character rows of DisplayFrame_LineWidth bytes from the buffer to the screen at DisplayFrame_Column / DisplayFrame_Row. It then copies the matching attributes from the buffer (offset by 6144) to the attribute file. The values in the snapshot describe rows of 4 frames of 8 by 10 characters, copied to column 25 row 3 after line 60.
DisplayFrame	64265	DI	Disable interrupts.
	64266	LD (65398),SP
	64270	LD SP,65470
	64273	LD A,(64259)
	64276	LD B,A
	64277	LD C,1
	64279	LD A,(64258)
	64282	DEC A
DisplayFrame_0	64283	CP B
	64284	JR C,DisplayFrame_1
	64286	SUB B
	64287	INC C
	64288	JR DisplayFrame_0
DisplayFrame_1	64290	INC A
	64291	LD B,A
	64292	LD HL,64260
	64295	XOR A
	64296	DEC B
	64297	JR Z,DisplayFrame_3
DisplayFrame_2	64299	ADD A,(HL)
	64300	DJNZ DisplayFrame_2
DisplayFrame_3	64302	LD B,C
	64303	LD C,A
	64304	LD HL,64261
	64307	XOR A
	64308	DEC B
	64309	JR Z,DisplayFrame_5
DisplayFrame_4	64311	ADD A,(HL)
	64312	DJNZ DisplayFrame_4
DisplayFrame_5	64314	LD L,A
	64315	CALL DisplayFrame_CalculateOffset
	64318	LD (64453),HL
	64321	SLA H
	64323	SLA H
	64325	SLA H
	64327	LD BC,(64256)
	64331	ADD HL,BC
	64332	EX DE,HL
	64333	LD A,(64263)
	64336	LD L,A
	64337	LD A,(64262)
	64340	LD C,A
	64341	CALL DisplayFrame_CalculateOffset
	64344	LD (64451),HL
	64347	SLA H
	64349	SLA H
	64351	SLA H
	64353	LD BC,16384
	64356	ADD HL,BC
	64357	EX DE,HL
	64358	LD A,(64261)
	64361	LD B,A
DisplayFrame_6	64362	PUSH BC
	64363	LD B,0
DisplayFrame_7	64365	LD A,(64264)
	64368	LD C,A
	64369	PUSH HL
	64370	PUSH DE
	64371	LDIR
	64373	POP DE
	64374	POP HL
	64375	CALL ScrollWindow_NextLine
	64378	EX DE,HL
	64379	CALL ScrollWindow_NextLine
	64382	EX DE,HL
	64383	JR NZ,DisplayFrame_7
	64385	POP BC
	64386	DJNZ DisplayFrame_6
	64388	LD HL,(64453)
	64391	LD BC,(64256)
	64395	ADD HL,BC
	64396	LD BC,6144
	64399	ADD HL,BC
	64400	EX DE,HL
	64401	LD HL,(64451)
	64404	LD BC,22528
	64407	ADD HL,BC
	64408	EX DE,HL
	64409	LD A,(64261)
	64412	LD IYl,A
	64414	LD B,0
DisplayFrame_8	64416	LD A,(64264)
	64419	LD C,A
	64420	PUSH HL
	64421	PUSH DE
	64422	LDIR
	64424	POP DE
	64425	POP HL
	64426	LD C,32
	64428	ADD HL,BC
	64429	EX DE,HL
	64430	ADD HL,BC
	64431	EX DE,HL
	64432	DEC IYl
	64434	JR NZ,DisplayFrame_8
	64436	LD SP,(65398)
	64440	RET