User manual

mikroPascal PRO for PIC32
MikroElektronika
229
Here is an example of using asm instructions :
program asm_example;
var myvar : word; absolute 0x2678;
const msg = 'Hello'; org 0x3678;
var myvar1 : dword;
procedure proc(); org 0x1234;
begin
asm
nop
end;
end;
begin
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;
end.
Asm code and SSA optimization
If asm code is mixed with the Pascal 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.