gpu mmio write addrs have been moved around

This commit is contained in:
minjaesong
2022-04-20 10:04:30 +09:00
parent 7cddb2660e
commit 219845e565
5 changed files with 44 additions and 34 deletions

View File

@@ -167,17 +167,12 @@ From the start of the memory space:
12 bytes
argument for "command" (arg1: Byte, arg2: Byte)
write to this address FIRST and then write to "command" to execute the command
2 bytes
framebuffer scroll X
2 bytes
framebuffer scroll Y
896 bytes
horizontal scroll offset for scanlines
234 bytes
1134 bytes
unused
1920
mapped to font ROM
Font Mapping area holds 128 characters in consecutive order, each character is always 15 bytes.
(designer's note: it's still useful to divide the char rom to two halves, lower half being characters ROM and upper half being symbols ROM)
2 bytes
Cursor position in: (y*80 + x)
2560 bytes
@@ -316,6 +311,12 @@ MMIO
22 12
23 21
If 1 layer is used, this field will do nothing and always fall back to 0
14..15 RW
framebuffer scroll X
16..17 RW
framebuffer scroll Y
1024..2047 RW
horizontal scroll offset for scanlines
Text-mode-font-ROM is immutable and does not belong to VRAM
Even in the text mode framebuffer is still being drawn onto the screen, and the texts are drawn on top of it