A question about pulling an item from he stack (ARM assembly)

[Iggypop]

STMFD R13!, {R14} (this puts an item on the stack)

LDMFD R13!, {R14} ???? does R13 not get decreased by 4 (goint up the stack) after memory access?

should i not use LDMFI R13!,{R14} ???

[SKS1]

It can be clearer to use STMDB sp!,{list} and LDMIA sp!,{list} rather than the FD suffix.

[Iggypop]

Ah yes, that makes sence!! but why than bother with FD and EI ?

[SKS1]

Ah yes, that makes sence!! but why than bother with FD and EI ?

Someone at the time thought that using aliases (...FD == LDMIA/STMDB) to represent stack configurations was a good idea! Can't imagine why, but that's me. Just write Push/Pull macros once, you're done.

[SKS1]

Ah yes, that makes sence!! but why than bother with FD and EI ?

Dug a little more into this. The original VLSI ARM data book did have these suffixes listed for stack use (FD, ED, FA, EA) in the Addressing Mode Names table in addition to the (to me more sensible) IA, IB, DA, DB modes, but the 1990 data book does not.

[Iggypop]

thank you for your insightfull answer...