alt Hacker NewsI don't think the Amiga has either parallel / per plane chip memory, or any need for backwards compatibility with CGA.
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ZFH • yesterday at 1:09 PM
It was all about saving RAM on the Amiga.
I don't think the Amiga has either parallel / per plane chip memory, or any need for backwards compatibility with CGA.
It was all about saving RAM on the Amiga.
Indeed. As per this timing diagram, Denise accesses each 16-bit word of each bitplane sequentially. Any bitplanes you turn off, the more cycles available for blitter... or CPU!
Fun fact! The Amiga Workbench is 4 colour hires by default, because hires is impressively businessy... but 8 or 16 colour hires would lock out the CPU most of the time, as the chipset would have to dip into the 68000's even cycle RAM accesses and stall it. 4 colour hires lets the CPU (on a chipmem-only system) run at full speed!
http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_gui...