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Diffstat (limited to 'newlib/libc/sys/arm/trap.S')
| -rw-r--r-- | newlib/libc/sys/arm/trap.S | 93 |
1 files changed, 0 insertions, 93 deletions
diff --git a/newlib/libc/sys/arm/trap.S b/newlib/libc/sys/arm/trap.S deleted file mode 100644 index 328fabc..0000000 --- a/newlib/libc/sys/arm/trap.S +++ /dev/null @@ -1,93 +0,0 @@ - /* Run-time exception support */ -#include "swi.h" - -/* .text is used instead of .section .text so it works with arm-aout too. */ - .text - .align 0 - .global __rt_stkovf_split_big - .global __rt_stkovf_split_small - -/* The following functions are provided for software stack checking. - If hardware stack-checking is being used then the code can be - compiled without the PCS entry checks, and simply rely on VM - management to extend the stack for a thread. - - The stack extension event occurs when the PCS function entry code - would result in a stack-pointer beneath the stack-limit register - value. The system relies on the following map: - - +-----------------------------------+ <-- end of stack block - | ... | - | ... | - | active stack | - | ... | <-- sp (stack-pointer) somewhere in here - | ... | - +-----------------------------------+ <-- sl (stack-limit) - | stack-extension handler workspace | - +-----------------------------------+ <-- base of stack block - - The "stack-extension handler workspace" is an amount of memory in - which the stack overflow support code must execute. It must be - large enough to deal with the worst case path through the extension - code. At the moment the compiler expects this to be AT LEAST - 256bytes. It uses this fact to code functions with small local - data usage within the overflow space. - - In a true target environment We may need to increase the space - between sl and the true limit to allow for the stack extension - code, SWI handlers and for undefined instruction handlers of the - target environment. */ - -__rt_stkovf_split_small: - mov ip,sp @ Ensure we can calculate the stack required - @ and fall through to... -__rt_stkovf_split_big: - @ in: sp = current stack-pointer (beneath stack-limit) - @ sl = current stack-limit - @ ip = low stack point we require for the current function - @ lr = return address into the current function - @ fp = frame-pointer - @ original sp --> +----------------------------------+ - @ | pc (12 ahead of PCS entry store) | - @ current fp ---> +----------------------------------+ - @ | lr (on entry) pc (on exit) | - @ +----------------------------------+ - @ | sp ("original sp" on entry) | - @ +----------------------------------+ - @ | fp (on entry to function) | - @ +----------------------------------+ - @ | | - @ | ..argument and work registers.. | - @ | | - @ current sp ---> +----------------------------------+ - @ - @ The "current sl" is somewhere between "original sp" and "current sp" - @ but above "true sl". The "current sl" should be at least 256bytes - @ above the "true sl". The 256byte stack guard should be large enough - @ to deal with the worst case function entry stacking (160bytes) plus - @ the stack overflow handler stacking requirements, plus the stack - @ required for the memory allocation routines. - @ - @ Normal PCS entry (before stack overflow check) can stack 16 - @ standard registers (64bytes) and 8 floating point registers - @ (96bytes). This gives a minimum stack guard of 160bytes (excluding - @ the stack required for the code). (Actually only a maximum of - @ 14standard registers are ever stacked on entry to a function). - @ - @ NOTE: Structure returns are performed by the caller allocating a - @ dummy space on the stack and passing in a "phantom" arg1 into - @ the function. This means that we do not need to worry about - @ preserving the stack under "sp" even on function return. - @ - @ Code should never poke values beneath sp. The sp register - @ should always be "dropped" first to cover the data. This - @ protects the data against any events that may try and use - @ the stack. - - SUB ip, sp, ip @ extra stack required for function - @ Add stack extension code here. If desired a new stack chunk - @ can be allocated, and the register state updated suitably. - - @ We now know how much extra stack the function requires. - @ Terminate the program for the moment: - swi SWI_Exit |