ask help about Assembly Language

robert_zhang — Sat, 16 Jan 2010 11:41:17 GMT

i study assembly language now,in function asm_set_ipl:

i see a instruction as following,but i dont konw the meaning of 8 that at the left of a6.in programer reference datasheet,i dont find the explanation,who can help me or tell me where can find some stuff about it?

move.l 8(A6),D6 /* get argument */

Re: ask help about Assembly Language

pgo — Sat, 16 Jan 2010 12:58:21 GMT

Dear Robert,

The instruction loads a longword (4 bytes) from the memory address calculated from the sum of A6 and an offset of 8 from the instruction. The longword is loaded into D6.

An example with numbers:

Say A6 contains 0x10000

mem[0x10008..0x1000B] => D6

It is likely that A6 is being used as a frame pointer and the 8 is an offset into the stack frame used to pass parameters to the function (from C code?).

bye

topic Re: ask help about Assembly Language in Classic/Legacy CodeWarrior

ask help about Assembly Language

Re: ask help about Assembly Language