Specifications

180 AMD Geode™ GeodeROM Functional Specification
Video BIOS Support
32087C
13.1.18.5 Subfunction 04h: Load 8x16 Font
Loads the ROM 8x16 font into the specified block. The font is loaded without changing the cell height or cursor size. If
the cell height needs to be changed, use Subfunction 14h to adjust the CRTC values. Eight different font blocks can be
loaded, but only two can be displayed at any one time.
Passed:
Returns:
None.
13.1.18.6 Subfunction 10h: Load User Font with Fixup
Loads the font for a range of characters and adjusts the cell height, cursor size, and vertical resolution. If the cell height
does not need to be changed, use Subfunction 00h. Eight different font blocks can be loaded, but only two can be dis-
played at any one time. The pointer to the font points to character 0 even if the starting character is non-zero.
The following rules must be followed:
1) No CRTC adjustments have been made since the previous mode set for the following calculations to be accurate.
2) Page zero must be active.
The BIOS variables are changed as follows:
Character height will be updated from BH Word variable at 0:485h
Display rows will be: INT ((200, 350, 400)/(char height) – 1 Byte variable at 0:484h
Regen length will be: (rows + 1) * columns * 2 Word variable at 0:44Ch
The CRTC adjustments are made as follows:
CRTC[09h] = Character height – 1 Max scan line
CRTC[0Ah] = Character height – 2 Cursor start
CRTC[0Bh] = Character height – 1 Cursor end
CRTC[12h] = (Rows + 1) *(character height) – 1 Vertical display end (single scanned modes)
CRTC[12h] = (Rows + 1) * (character height) * 2) – 1 Vertical display end (double scanned modes)
CRTC[14h] = Character height – 1 Underline location (monochrome modes only)
Passed:
Returns:
None.
Parameter Description
AH 11h
AL 04h
BL Font block
Parameter Description
AH 11h
AL 10h
BH Number of bytes per character (character height)
BL Font block
CX Number of characters to load
DX Starting character
ES:BP Pointer to font