TMS320F280049: DCL shadowed context save/restore

Jack Tan80

Dear C2000 expert,

The DCL source code show a method of enabling shadowed context save/restore, but this feature is disable by default, can you please help me know if it have risks of using shadowed context save/restore?

And I didn't find the description about SAVE&RESTORE instruction, can you please me know which docs have demonstrate those 2 instructions?

FASTCR_DF22_C3 .set 0 ; set to 1 to enable shadowed context save/restore

_DCL_runDF22_C3:
.asmfunc
.if FASTCR_DF22_C3 = 0
MOV32 *SP++, R4H
MOV32 *SP++, R5H
MOV32 *SP++, R6H
MOV32 *SP++, R7H
.else
SAVE
.endif

over 5 years ago

0 Jack Tan80 over 5 years ago

Mastermind 7160 points

Dear TI expert,

May I get response in this post? Thanks...

0 Han Zhang6 over 5 years ago

TI__Expert 7835 points

The SAVE/RESTORE instruction are documented in the below document. There is only one set of shadow register for fast context save / restore of FPU registers. Hence you cannot do multiple level of save before calling restore.

The SAVE and RESTORE instructions should be used in high-priority interrupts. That is interrupts that cannot themselves be interrupted.

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TMS320F280049: DCL shadowed context save/restore