[U-Boot] Is it necessary that uboot(mips) should read status register($12) before setting it

Hi all,

MIPS Uboot works OK.Part of the code is as below.

And my questions: 1.read status register($12) and save value to $10,but don't use the value in $10 to do anything. Because uboot overwrite $10.

2.Is it right?I can delete this code "mfc0 $10,$12" from uboot.

Thanks.

Bruce

# Initialize Misc. Cop0 state

# Read status register mfc0 $10, $12 //Can I delete this code?

# Set up Status register: # Disable Coprocessor Usable bits # Turn off Reduce Power bit # Turn off reverse endian # Turn off BEV (use normal exception vectors) # Clear TS, SR, NMI bits # Clear Interrupt masks # Clear User Mode # Clear ERL # Set EXL # Clear Interrupt Enable # modify by Bruce #li $11, 0x0000ff02 li $11, 0x00000004 mtc0 $11, $12

# Disable watch exceptions mtc0 $0, $18

# Clear Watch Status bits li $11, 0x3 mtc0 $11, $19

# Clear WP bit to avoid watch exception upon user code entry # Clear IV bit - Interrupts go to general exception vector # Clear software interrupts mtc0 $0, $13

# Set KSeg0 to cacheable # Config.K0 mfc0 $10, $16 //Overwrite $10 register.Why uboot read status register($12) and save value to $10,but don't use $10.

li $11, 0x7 not $11 and $10, $11 or $10, 0x3 mtc0 $10, $16