xorl %eax, %eax
movw 18(%di), %ax
movl %eax, %fs:(PARAM_LFB_SIZE)
+
+# switching the DAC to 8-bit is for <= 8 bpp only
+ movw %fs:(PARAM_LFB_DEPTH), %ax
+ cmpw $8, %ax
+ jg dac_done
+
+# get DAC switching capability
+ xorl %eax, %eax
+ movb 10(%di), %al
+ testb $1, %al
+ jz dac_set
+
+# attempt to switch DAC to 8-bit
+ movw $0x4f08, %ax
+ movw $0x0800, %bx
+ int $0x10
+ cmpw $0x004f, %ax
+ jne dac_set
+ movb %bh, dac_size # store actual DAC size
+
+dac_set:
+# set color size to DAC size
+ movb dac_size, %al
+ movb %al, %fs:(PARAM_LFB_COLORS+0)
+ movb %al, %fs:(PARAM_LFB_COLORS+2)
+ movb %al, %fs:(PARAM_LFB_COLORS+4)
+ movb %al, %fs:(PARAM_LFB_COLORS+6)
+
+# set color offsets to 0
+ movb $0, %fs:(PARAM_LFB_COLORS+1)
+ movb $0, %fs:(PARAM_LFB_COLORS+3)
+ movb $0, %fs:(PARAM_LFB_COLORS+5)
+ movb $0, %fs:(PARAM_LFB_COLORS+7)
+
+dac_done:
# get protected mode interface informations
movw $0x4f0a, %ax
xorw %bx, %bx
ret
store_edid:
- pushw %es # just save all registers
- pushw %ax
+ pushw %es # just save all registers
+ pushw %ax
pushw %bx
pushw %cx
pushw %dx
pushw %di
- pushw %fs
+ pushw %fs
popw %es
movl $0x13131313, %eax # memset block with 0x13
movw $32, %cx
- movw $0x440, %di
+ movw $0x140, %di
cld
- rep
- stosl
+ rep
+ stosl
- movw $0x4f15, %ax # do VBE/DDC
+ movw $0x4f15, %ax # do VBE/DDC
movw $0x01, %bx
movw $0x00, %cx
- movw $0x01, %dx
- movw $0x440, %di
- int $0x10
+ movw $0x00, %dx
+ movw $0x140, %di
+ int $0x10
- popw %di # restore all registers
+ popw %di # restore all registers
popw %dx
popw %cx
popw %bx
popw %ax
- popw %es
+ popw %es
ret
# VIDEO_SELECT-only variables
do_restore: .byte 0 # Screen contents altered during mode change
svga_prefix: .byte VIDEO_FIRST_BIOS>>8 # Default prefix for BIOS modes
graphic_mode: .byte 0 # Graphic mode with a linear frame buffer
+dac_size: .byte 6 # DAC bit depth
# Status messages
keymsg: .ascii "Press <RETURN> to see video modes available, "