I have an assignment to do but all of the topics have not been thoroughly discussed in class. We are coding in assembly (SPARC). This is the assignment:
Write an assembly program to test if the flag 0x10 is set in the register %l0. If it is set, then multiply the content of %l0 by 2 using the appropriate shift instruction and exit immediately. If it is not set, then divide the content of %l0 by 2 using the appropriate shift instruction and exit. You may test your program when %l0 is equal to 0x18 and when %l0 is equal to 0x08.
This is the code I have so far:
.global main
main:
save %sp,-96,%sp
clr %l0
clr %l1
mov 0x10,%l1
btst 0x10,%l0 !Test if a bit/s clear or set
be clear !Goto
nop
set:
sll %l1,1,%l3 !shift %l0 left (%l0*2)
ba exit
clear:
srl %l1,1,%l3 !shift %l0 right (%l0/2)
ba exit
exit:
mov 1,%g1 !Exit
ta 0
What does set and clear mean? When using btst, what occurs? What is the correct format for best? Are my shift left and shift right(to multiply and divide) done correctly?
I have tried to look through the site and google as well, however I cannot come up with any thorough explanation for this.
thank you
