User manual

232
mikoBasic PRO for PIC32
MikroElektronika
- Accessing local variable: <routine_name>_<variable_name>.
- Accessing routine parameter: FARG_<routine_name>_<variable_name>.
Here is an example of using asm instructions :
program asm_example
dim myvar as word absolute 0x2678
dim myvar1 as longword
const msg = “Hello” org 0x1234
sub procedure proc() org 0x2346
asm
nop
end asm
end sub
main:
myvar = 5
myvar1 = 0xABCD1234
asm
MOV _myvar, w0 ; move myvar to W0
nop
MOV #6, W0 ; move literal 6 to W0
MOV W0, _myvar ; move contents of W0 to myvar
MOV #lo_addr(_myvar), w1 ; retrieve low address word of _myvar and move
it to W1 (0x2678 -> W1)
MOV #hi_addr(_myvar), W1 ; retrieve high address word of _myvar and move
it to W1 (0x0000 -> W1)
MOV #lo_addr(_proc), W0 ; retrieve hi address byte of routine proc and
move it to W0 (0x0001 -> W1)
MOV #lo_addr(_msg), W0 ; retrieve low address word of constant msg and
move it to W0 (0x3652 -> W1)
MOV _myvar1+2, w0 ; accessing hi word of myvar1 variable and move
it to W1 (0xABCD -> W1)
end asm
end.
Asm code and SSA optimization
If asm code is mixed with the Basic code, keep in mind that the generated code can substantially differ when SSA
optimization option is enabled or disabled.
This is due to the fact that SSA optimization uses certain working registers to store routine parameters (W10-W13),
rather than storing them onto the function frame.
Because of this, user must be very careful when writing asm code as existing values in the working registers used by
SSA optimization can be overwritten.
To avoid this, it is recommended that user includes desired asm code in a separate routine.