Freescale Semiconductor StarCore SC140 - Manual (Page 722)

A-408 SC140 DSP Core Reference Manual
TFRA
TFRA
Move the Other Stack Pointer
TFRA
to/from a Register (AGU)
Description
Status and Conditions that Affect Instruction
Status and Conditions Changed by Instruction
None
Operation Assembler Syntax
If ( SR [EXP] = 1), then NSP
→ Rn
else ESP
→ Rn
TFRA OSP,Rn
If ( SR [EXP] = 1), then Rn
→ NSP
else Rn
→ ESP
TFRA Rn,OSP
TFRA OSP,Rn
Writes the value of the inactive (other) stack pointer (OSP) to an address register (Rn). If EXP ( SR [18]) is
set, then OSP is the normal stack pointer (NSP). Otherwise, OSP is the exception stack pointer (ESP).
TFRA Rn,OSP
Writes the contents of an address register (Rn) to the inactive (other) stack pointer (OSP). If EXP ( SR [18])
is set, then OSP is the normal stack pointer (NSP). Otherwise, OSP is the exception stack pointer (ESP).
Note: The value in NSP or ESP will have the lower three bits equal to zero.
Register Address Bit Name Description
SR[18] EXP Determines which stack pointer is used and execution working mode.