|
Revision 1663, 1.0 KB
(checked in by philmoz, 3 months ago)
|
|
Merged revision(s) 1662 from branches/release-1_0:
|
-
Property svn:eol-style set to
native
|
| Line | |
|---|
| 1 | #ifndef ASMSAFE_H |
|---|
| 2 | #define ASMSAFE_H |
|---|
| 3 | /* |
|---|
| 4 | macros to safely call C functions from most inline ASM |
|---|
| 5 | these should replace the use of __attribute__((naked)) functions for C code, |
|---|
| 6 | because C code is not actually legal in naked functions and can break in obscure ways. |
|---|
| 7 | see http://chdk.wikia.com/wiki/CHDK_Coding_Guidelines#Naked_functions |
|---|
| 8 | usage |
|---|
| 9 | asm volatile ( |
|---|
| 10 | ... |
|---|
| 11 | ASM_SAFE("BL my_func\n") |
|---|
| 12 | ... |
|---|
| 13 | ) |
|---|
| 14 | |
|---|
| 15 | you can set up arguments for the function inside the ASM_SAFE without worrying about preserving values |
|---|
| 16 | e.g |
|---|
| 17 | ASM_SAFE( |
|---|
| 18 | "MOV R0,#1\n" |
|---|
| 19 | "BL my_func\n" |
|---|
| 20 | ) |
|---|
| 21 | */ |
|---|
| 22 | |
|---|
| 23 | // push all regs except SP and PC |
|---|
| 24 | // push CSPR via R0 |
|---|
| 25 | // restore value for R0 from stack |
|---|
| 26 | #define ASM_SAFE_ENTER \ |
|---|
| 27 | "STMFD SP!, {R0-R12,LR}\n" \ |
|---|
| 28 | "MRS R0, CPSR\n" \ |
|---|
| 29 | "STR R0,[SP,#-4]!\n" \ |
|---|
| 30 | "LDR R0,[SP,#4]\n" |
|---|
| 31 | |
|---|
| 32 | // pop CSPR via R0 |
|---|
| 33 | // pop all regs except SP and PC |
|---|
| 34 | #define ASM_SAFE_LEAVE \ |
|---|
| 35 | "LDR R0,[SP],#4\n" \ |
|---|
| 36 | "MSR CPSR_cxsf,R0\n" \ |
|---|
| 37 | "LDMFD SP!, {R0-R12,LR}\n" |
|---|
| 38 | |
|---|
| 39 | #define ASM_SAFE(asmcode) \ |
|---|
| 40 | ASM_SAFE_ENTER \ |
|---|
| 41 | asmcode \ |
|---|
| 42 | ASM_SAFE_LEAVE |
|---|
| 43 | |
|---|
| 44 | #endif // ASMSAFE_H |
|---|
