If bits 6 and 7 are 3, then the divisor should be 1 instead of 16.
0 -> 2x
1 -> 4x
2 -> 8x
3 -> 1x (not 16x).
This change affects RGB 12 inch dislay 512 x 384 60Hz mode in Platinum.
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).
Switching from Watch to Arrow cursor at vertical position zero (top of the screen) would sometimes cut off the top half of the Arrow cursor. The following changes fix this:
Use the new cursor_dirty flag to signal when the cursor should be updated. This reduces the number of cursor updates and doesn't depend on registers being accessed in a specific order.
Set the cursor_dirty flag for any change that should cause the hardware cursor to be updated:
- CUR_CLR0, CUR_CLR1: Cursor color changes. We don't check if the colors actually changed (all cursors are usually black and white). Rather, writes to these registers usually means the cursor bytes have changed or will change.
- CUR_OFFSET: Offset to cursor bytes.
- CUR_VERT_OFF: First vertical line of cursor to draw.
Other changes that don't require the cursor to be updated:
- CUR_HORZ_OFF: Horizontal offset of cursor position. The cursor is unchanged - just need to adjust the drawing position.
- CUR_HORZ_VERT_POSN: The cursor is unchanged - only the drawing position is changed.
The only thing that could change the cursor that we don't check is a change to the cursor bytes.
Sense codes for displays like the 12 inch RGB display (512x384) weren't working since they had the extended part set to 0xff.
Related to issues #25.
Also added some descriptive information and sizes which may be used for UI purposes such as creating a menu of displays to choose from. The sizes may be used to set the default window size for the display.
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.
