Int 15/AX=DA01h

AMI PCI BIOS - CPU SPEED CONTROL

AX = DA01h
CL = subfunction (00h-02h)
00h set low CPU speed
01h set high CPU speed
02h get current CPU speed

Return:
CF clear if successful
AH = current/new CPU speed (00h low, 01h high)
AL = ??? (00h)
CF set on error
AH = error code (86h unsupported subfunction)

Notes: In the v1.00.05.AX1 BIOS, subfunctions 00h and 01h are NOPs in both protected and V86 modes due to a test of MSW bit 0. Setting the CPU speed also generates the same audible signals generated when manually switching speeds with Ctrl-Alt-Gray- and Ctrl-Alt-Gray+

BUG: The BIOS apparently intends to return CF set if ???, but fails to use a different exit path in that case, resulting in CF clear

Category: Vendor-specific BIOS Extensions - Int 15h - A

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