#endif /* IN_LIBGCC2 */
#define TARGET_ARCH64 (! TARGET_ARCH32)
-/* Code model selection.
- -mcmodel is used to select the v9 code model.
- Different code models aren't supported for v7/8 code.
-
- TARGET_CM_32: 32 bit address space, top 32 bits = 0,
- pointers are 32 bits. Note that this isn't intended
- to imply a v7/8 abi.
-
- TARGET_CM_MEDLOW: 32 bit address space, top 32 bits = 0,
- avoid generating %uhi and %ulo terms,
- pointers are 64 bits.
-
- TARGET_CM_MEDMID: 64 bit address space.
- The executable must be in the low 16 TB of memory.
- This corresponds to the low 44 bits, and the %[hml]44
- relocs are used. The text segment has a maximum size
- of 31 bits.
-
- TARGET_CM_MEDANY: 64 bit address space.
- The text and data segments have a maximum size of 31
- bits and may be located anywhere. The maximum offset
- from any instruction to the label _GLOBAL_OFFSET_TABLE_
- is 31 bits.
-
- TARGET_CM_EMBMEDANY: 64 bit address space.
- The text and data segments have a maximum size of 31 bits
- and may be located anywhere. Register %g4 contains
- the start address of the data segment.
-*/
+/* Code model selection in 64-bit environment.
+
+ The machine mode used for addresses is 32-bit wide:
+
+ TARGET_CM_32: 32-bit address space.
+ It is the code model used when generating 32-bit code.
+
+ The machine mode used for addresses is 64-bit wide:
+
+ TARGET_CM_MEDLOW: 32-bit address space.
+ The executable must be in the low 32 bits of memory.
+ This avoids generating %uhi and %ulo terms. Programs
+ can be statically or dynamically linked.
+
+ TARGET_CM_MEDMID: 44-bit address space.
+ The executable must be in the low 44 bits of memory,
+ and the %[hml]44 terms are used. The text and data
+ segments have a maximum size of 2GB (31-bit span).
+ The maximum offset from any instruction to the label
+ _GLOBAL_OFFSET_TABLE_ is 2GB (31-bit span).
+
+ TARGET_CM_MEDANY: 64-bit address space.
+ The text and data segments have a maximum size of 2GB
+ (31-bit span) and may be located anywhere in memory.
+ The maximum offset from any instruction to the label
+ _GLOBAL_OFFSET_TABLE_ is 2GB (31-bit span).
+
+ TARGET_CM_EMBMEDANY: 64-bit address space.
+ The text and data segments have a maximum size of 2GB
+ (31-bit span) and may be located anywhere in memory.
+ The global register %g4 contains the start address of
+ the data segment. Programs are statically linked and
+ PIC is not supported.
+
+ Different code models are not supported in 32-bit environment. */
enum cmodel {
CM_32,
is done just by pretending it is already truncated. */
#define TRULY_NOOP_TRUNCATION(OUTPREC, INPREC) 1
-/* Specify the machine mode that pointers have.
- After generation of rtl, the compiler makes no further distinction
- between pointers and any other objects of this machine mode. */
+/* Specify the machine mode used for addresses. */
#define Pmode (TARGET_ARCH64 ? DImode : SImode)
/* Generate calls to memcpy, memcmp and memset. */
@item -mcmodel=medlow
@opindex mcmodel=medlow
-Generate code for the Medium/Low code model: the program must be linked
-in the low 32 bits of the address space. Pointers are 64 bits.
-Programs can be statically or dynamically linked.
+Generate code for the Medium/Low code model: 64-bit addresses, programs
+must be linked in the low 32 bits of memory. Programs can be statically
+or dynamically linked.
@item -mcmodel=medmid
@opindex mcmodel=medmid
-Generate code for the Medium/Middle code model: the program must be linked
-in the low 44 bits of the address space, the text segment must be less than
-2G bytes, and data segment must be within 2G of the text segment.
-Pointers are 64 bits.
+Generate code for the Medium/Middle code model: 64-bit addresses, programs
+must be linked in the low 44 bits of memory, the text and data segments must
+be less than 2GB in size and the data segment must be located within 2GB of
+the text segment.
@item -mcmodel=medany
@opindex mcmodel=medany
-Generate code for the Medium/Anywhere code model: the program may be linked
-anywhere in the address space, the text segment must be less than
-2G bytes, and data segment must be within 2G of the text segment.
-Pointers are 64 bits.
+Generate code for the Medium/Anywhere code model: 64-bit addresses, programs
+may be linked anywhere in memory, the text and data segments must be less
+than 2GB in size and the data segment must be located within 2GB of the
+text segment.
@item -mcmodel=embmedany
@opindex mcmodel=embmedany
Generate code for the Medium/Anywhere code model for embedded systems:
-assume a 32-bit text and a 32-bit data segment, both starting anywhere
-(determined at link time). Register %g4 points to the base of the
-data segment. Pointers are still 64 bits.
-Programs are statically linked, PIC is not supported.
+64-bit addresses, the text and data segments must be less than 2GB in
+size, both starting anywhere in memory (determined at link time). The
+global register %g4 points to the base of the data segment. Programs
+are statically linked and PIC is not supported.
@item -mstack-bias
@itemx -mno-stack-bias
git://gcc.gnu.org / gcc.git / commitdiff