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*Hello, All!* Procedures required: 1. Calculate the screen address based on pixel coordinates. 2. Calculation of the address in the attributes based on the screen address. /That’s all, All, you can scroll further.../

Hello Alexander. Tue 3 Jun 02 Alexander Bondarenko -> All: Uwaaah! AB> 1. Calculation of the screen address based on pixel coordinates. AB> 2. Calculation of the address in attributes based on the screen AB> addresses. If there are no restrictions, then write that way ;))) I can advise you to paint a sign with the addresses of all points on the screen and search in it. 11 ADD HL,SP //start. signs + (pixel number*2) 10 POP rr -- 21 measures Thank you for your attention.

On Tue, 03 Jun 2003 22:39:00 +0400, Alexander Bondarenko wrote: AB> 1. Calculation of the screen address based on pixel coordinates. AB> 2. Calculation of the address in attributes based on the screen address. Bitmap address on screen, 16-bit word, bits (most significant on the left): B1 B0 e0 L4 L3 y2 y1 y0 L2 L1 L0 C4 C3 C2 C1 C0 Screen color address: B1 B0 0 1 1 0 L4 L3 L2 L1 L0 C4 C3 C2 C1 C0 B0,1 = bank 5 or 7 (low two bits) e0 = odd familiarity in 512x192 mode, otherwise 0. L4,3,2,1,0 = familiarity along the Y coordinate (0..23) y2,1,0 = pixel at Y coordinate (0..7) C4,3,2,1,0 = familiarity along the X coordinate (0..31) the origin point is in the upper left corner of the screen, Y coordinate is vertical, X is horizontal axis. Now for your questions: P.1 (y>>3)&0x18|bank|(y&7)|((y<<5)&0xe0)|((x>>3)&0x1f) depending on bank number and registers used is possible optimization of the assembler program... P.2 (address>>3)&7|0x18|bank depending on bank number and registers used is possible optimization of the assembler program... -- [ZX]