So I have been staring at this code for the last half and hour and I can say I completely understand it. I changed the format of sw function because it is written in a different way. However the program is not recognizing LCO for some reason. I am getting an error
Also should the print function in the end still be calling to r31? It can't call to r14 because the original value of r14 gets restored after a few stepsCode:unrecognized operand specifier
Modified code thanks to you!
Code:.global _open .global _close .global _read .global _write .global _printf .global _a .align 4 _a: .word 13 LC0: .ascii "output is %d\12\0" .align 4 .global _main _main: ;;; ; ; Initialize Stack Pointer add r14,r0,r0 lhi r14, ((memSize-4)>>16)&0xffff addui r14, r14, ((memSize-4)&0xffff) ;;; ; ; Save the old frame pointer sw -4(r14),r30 ;;; ; ; Save the return address sw -8(r14),r31 ;;; ; ; Establish new frame pointer add r30,r0,r14 ;;; ; ; Adjust Stack Pointer add r14,r14,#-24 ;;; ; ; Save Registers sw 0(r14),r3 sw 4(r14),r4 sw 8(r14),r5 lhi r3,(_a>>16)&0xffff addui r3,r3,(_a&0xffff) subi r5,r0,#1 lw r4,0(r3) beqz r4, _l2 _l1: addi r5,r5,#1 srli r4, r4,#1 bnez r4,_l1 _l2: subi r14,r14,#8 lhi r3,(LCO>>16)&0xffff addui r3,r3,(LCO&0xffff) sw 0(r14),r3 sw 4(r14),r5 jal _printf addi r14,r14,#8 L3: ;;; ; ; Restore the saved registers lw r3,-24(r30) nop lw r4,-20(r30) nop lw r5,-16(r30) nop ;;; ; ; Restore return address lw r31,-8(r30) nop ;;; ; ; Restore stack pointer add r14,r0,r30 ;;; ; ; Restore frame pointer lw r30,-4(r30) ;;; ; ; HALT jal _exit nop _exit: trap #0 jr r31 nop _open: trap #1 jr r31 nop _close: trap #2 jr r31 nop _read: trap #3 jr r31 nop _write: trap #4 jr r31 nop _printf: trap #5 jr r31 nop
Is there a reason that 4 isn't printing
r5 is incremented 4 times and when we
and call printf after it should printCode:sw 4(r14), r5
r5 is initialized to -1 since log(0) = -1, log(1) = 0, log(2) = 1, log(4) = 2, log(8) = 3. If r5 is incremented 4 times, it should be 3.Originally Posted by kiwi101
Is the _printf not working? Do you even see "the output is ..." ?
No I can't see anything with the above code I posted there is an error:
Code:pr.s(45): unrecognizable operand specifier: lhi r3, => (LCO>>16)&0xffff pr.s(46): unrecognizable operand specifier: addui r3,r3, => (LCO&0xffff)
I don't know why it can not recognize LCO
Isn't that label LC0 (L C zero)?
Once you get done with the DLX, you should switch to learning X86 (Intel) assembly code, assuming you're running on a PC. There are more instructions to learn, but there are fewer limitations that you have to work around, such as the DLX limitation of 16 bit immediate values. The other issue for X86 assembly is the actual names of the library functions as called from assembly, but in this case, you can write a small c program that calls the functions you want to use, then have the compiler produce assembly code and use that as a reference.
AHH I'm such a dummy
But now this is what is printing
Code:TRAP #0 received
Even if i change the printf r31 in the end to printf r5
some other error appears
I'm so close this is sooo frustrating!!!
trap #0 is normal program exit. I don't know why the printf did not display anything. Is there a console window open while the program is running? Can you run the program from a console window so that you can see program output?
r31 contains the return address, you should not change that to r5.printf r31
I actually have no idea what a console window is
So I'm assuming no its not open.
Should I download a console window to run it on
Is there some way to ask for user input like scanf or gets, or to pause the screen until the user presses some key? If so, try that to see if a console window appears. It could be that the program opens a console window automatically, but then closes it when the program completes (trap #0), and it's not on long enough to be visible.
Are there any instructions that came with the DLX tool set that you have?
