The command ORG

[zetropix]

I cant understand the function of ORG exactly...

Thank you

 

[ericgibbs]

I cant understand the function of ORG exactly...

Thank you

ORG is short for Origin.

Its what the Assembler uses as the start of the Program Counter in the program.

Example:
ORG 0x0000 ; would tell the assembler to start the Program Counter at 0000

ORG 0x0004 ; would tell the assembler to start the Program Counter at 0004


Do you follow. OK.?

 

[ArtemisGoldfish]

I thought ORG moves the following code up to the memory address given.

Expanding upon what I said, just for clarity, I mean that if you go

ORG 0x0004
(something)
ORG 0x0008
(something)

It'd end up compiling into NOP's until 0x0004, the instruction, then NOP's until 0x0008.

 

[Nigel Goodwin]

I thought ORG moves the following code up to the memory address given.

It doesn't 'move' anything, it just sets the current address, so everything after it will be assembled from that address onwards - it's a directive to the assembler.

 

[ArtemisGoldfish]

It doesn't 'move' anything, it just sets the current address, so everything after it will be assembled from that address onwards - it's a directive to the assembler.

Yeah, that's what I meant.

 

[ericgibbs]

I thought ORG moves the following code up to the memory address given.

Expanding upon what I said, just for clarity, I mean that if you go

ORG 0x0004
(something)
ORG 0x0008
(something)

It'd end up compiling into NOP's until 0x0004, the instruction, then NOP's until 0x0008.

hi AG,

It wouldnt fill the gaps in ORG 0x0004 to ORG 0x0008 with NOP's if the 'something' in your example was a program/assembler instruction.

 

[Nigel Goodwin]

hi AG,

It wouldnt fill the gaps in ORG 0x0004 to ORG 0x0008 with NOP's if the 'something' in your example was a program/assembler instruction.

No, it won't create any code for those addresses - unless it's been told to.

 

[ericgibbs]

No, it won't create any code for those addresses - unless it's been told to.

It wouldnt fill the gaps in ORG 0x0004 to ORG 0x0008 with NOP's if the 'something' in your example was a program/assembler instruction.

Isn't that what I said.

The program memory will be 3fff for the unused locations.