The JS implementation does content hashing to not blit unchanged
framebuffer contents (see mihaip/dingusppc@171ff2d407).
However, that is not necessary for the ATI adapters that already track
this and only set draw_fb if the framebuffer has actually changed.
Pass through a fb_known_to_be_changed for these cases, and also add an
optional update_skipped method (since the JS still wants to know when
the last logical screen update was).
This commit fixes conflict resolution mistakes in the following commits:
"atimach64gx: Let crtc_update calculate fb_ptr."
"atimach64gx: Redraw only when necessary."
"atimach64gx: Log unhandled overlay registers." was mistakenly included in "atimach64gx: Let crtc_update calculate fb_ptr.". The OVR_ registers were included because they may be needed for 2D acceleration in System 7.5.3 and later.
Init them to defaults.
Make CONFIG_CNTL 8 bytes so unaligned read/write is easier.
Write changes to CONFIG_CNTL even if offset + size is > 4.
Log aperture change only if first byte (LSB) of CONFIG_CNTL is written. The driver might only write to the 2 most significant bytes which won't affect aperture size.
Offset and size are applied to the destination, not to source value, so we shouldn't use extract_bits when logging value.
Use ATI bitfield enums in switch statement.
- Read 8 bytes at a time instead of just 1.
- Remove multiply operations from loop. We just need increments or additions.
- Change compares with int to compares with zero.
CUR_HORZ_OFF becomes non-zero when the cursor needs to be drawn to the left of the left edge of the frame buffer.
CUR_VERT_OFF is handled differently. When CUR_VERT_OFF is non-zero, CUR_OFFSET is changed to point to the first line of the cursor that will be drawn, so CUR_VERT_OFF is the number of lines to remove from the total height of the cursor.
Alternatively, we could handle CUR_VERT_OFF the same way as CUR_HORZ_OFF by leaving the cursor height constant, drawing the cursor starting from the CUR_VERT_OFF line, and adjusting cursor Y position by negative CUR_VERT_OFF.
This method is used by both pci_io_read and pci_io_write to determine if ISA type I/O access is allowed.
The SPARSE_IO_BASE I/O address is defined. This I/O range is not defined by an I/O BAR.
