vga_setreadpage man page
vga_setreadpage — set the 64K SVGA page number
void vga_setreadpage(int page);
Usually SVGA cards have more than the 64K memory which suffice for an ordinary VGA. However, the memory window mapped at vga_getgraphmem(3) is only 64K bytes large. vga_setreadpage() selects the page-th 64K memory chunk to be visible for reads at position vga_getgraphmem(3).
vga_setwritepage(3) allows a different 64K memory chunk to be modified by writes to this memory window. This is a very useful feature for screen to screen pixmap copies. However, not all cards support this in all graphics mode. Check vga_modeinfo(3) for availability. Esp. as this feature can also not be used when in background mode.
Of course, this function must be used in conjunction with vga_setwritepage(3) but may not be used in conjunction with vga_setpage(3).
svgalib(7), vgagl(7), libvga.config(5), fun(6), vgatest(6), vga_claimvideomemory(3), vga_getgraphmem(3), vga_modeinfo(3), vga_setpage(3), vga_setwritepage(3), vga_setlinearaddressing(3)
This manual page was edited by Michael Weller <email@example.com>. The exact source of the referenced function as well as of the original documentation is unknown.
It is very likely that both are at least to some extent are due to Harm Hanemaayer <H.Hanemaayer@inter.nl.net>.
Occasionally this might be wrong. I hereby asked to be excused by the original author and will happily accept any additions or corrections to this first version of the svgalib manual.
svgalib(7), vga_ext_set(3), vga_getgraphmem(3), vga_getmodeinfo(3), vga_runinbackground(3), vga_setlinearaddressing(3), vga_setpage(3), vga_setwritepage(3).