The Stack Low Register (SLR) stores the stack low limit use to detect stack overflow. When the address of a load or store instruction using the stack pointer (register R1) as rA is less than the Stack Low Register, a stack overflow occurs, causing a Stack Protection Violation exception if exceptions are enabled in MSR.
When read with the MFS instruction, the SLR is specified by setting Sa = 0x0800. The following figure illustrates the SLR register and the following table provides bit descriptions and reset values.
When 64-bit MicroBlaze is
enabled (
C_DATA_SIZE = 64), the Stack Low Register
has up to 64 bits, according to the C_ADDR_SIZE
parameter, otherwise it has 32 bits.Note: The
register is only implemented if stack protection is enabled by setting the
parameter
C_USE_STACK_PROTECTION to 1. If stack
protection is not implemented, writing to the register has no
effect.Note: Stack protection is
not available when the MMU is enabled (
C_USE_MMU > 0). With the MMU page-based memory protection is
provided through the UTLB instead.Figure 1. SLR
| Bits 1 | Name | Description | Reset Value |
|---|---|---|---|
|
0:31 0:C_ADDR_SIZE-1 |
SLR | Stack Low Register | 0x0 |
|
|||