+++ /dev/null
-This is doc/gccint.info, produced by makeinfo version 4.5 from
-doc/gccint.texi.
-
-INFO-DIR-SECTION Programming
-START-INFO-DIR-ENTRY
-* gccint: (gccint). Internals of the GNU Compiler Collection.
-END-INFO-DIR-ENTRY
- This file documents the internals of the GNU compilers.
-
- Published by the Free Software Foundation
-59 Temple Place - Suite 330
-Boston, MA 02111-1307 USA
-
- Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-1999, 2000, 2001, 2002 Free Software Foundation, Inc.
-
- Permission is granted to copy, distribute and/or modify this document
-under the terms of the GNU Free Documentation License, Version 1.1 or
-any later version published by the Free Software Foundation; with the
-Invariant Sections being "GNU General Public License" and "Funding Free
-Software", the Front-Cover texts being (a) (see below), and with the
-Back-Cover Texts being (b) (see below). A copy of the license is
-included in the section entitled "GNU Free Documentation License".
-
- (a) The FSF's Front-Cover Text is:
-
- A GNU Manual
-
- (b) The FSF's Back-Cover Text is:
-
- You have freedom to copy and modify this GNU Manual, like GNU
-software. Copies published by the Free Software Foundation raise
-funds for GNU development.
-
-\1f
-File: gccint.info, Node: Machine Constraints, Prev: Modifiers, Up: Constraints
-
-Constraints for Particular Machines
------------------------------------
-
- Whenever possible, you should use the general-purpose constraint
-letters in `asm' arguments, since they will convey meaning more readily
-to people reading your code. Failing that, use the constraint letters
-that usually have very similar meanings across architectures. The most
-commonly used constraints are `m' and `r' (for memory and
-general-purpose registers respectively; *note Simple Constraints::), and
-`I', usually the letter indicating the most common immediate-constant
-format.
-
- For each machine architecture, the `config/MACHINE/MACHINE.h' file
-defines additional constraints. These constraints are used by the
-compiler itself for instruction generation, as well as for `asm'
-statements; therefore, some of the constraints are not particularly
-interesting for `asm'. The constraints are defined through these
-macros:
-
-`REG_CLASS_FROM_LETTER'
- Register class constraints (usually lower case).
-
-`CONST_OK_FOR_LETTER_P'
- Immediate constant constraints, for non-floating point constants of
- word size or smaller precision (usually upper case).
-
-`CONST_DOUBLE_OK_FOR_LETTER_P'
- Immediate constant constraints, for all floating point constants
- and for constants of greater than word size precision (usually
- upper case).
-
-`EXTRA_CONSTRAINT'
- Special cases of registers or memory. This macro is not required,
- and is only defined for some machines.
-
- Inspecting these macro definitions in the compiler source for your
-machine is the best way to be certain you have the right constraints.
-However, here is a summary of the machine-dependent constraints
-available on some particular machines.
-
-_ARM family--`arm.h'_
-
- `f'
- Floating-point register
-
- `F'
- One of the floating-point constants 0.0, 0.5, 1.0, 2.0, 3.0,
- 4.0, 5.0 or 10.0
-
- `G'
- Floating-point constant that would satisfy the constraint `F'
- if it were negated
-
- `I'
- Integer that is valid as an immediate operand in a data
- processing instruction. That is, an integer in the range 0
- to 255 rotated by a multiple of 2
-
- `J'
- Integer in the range -4095 to 4095
-
- `K'
- Integer that satisfies constraint `I' when inverted (ones
- complement)
-
- `L'
- Integer that satisfies constraint `I' when negated (twos
- complement)
-
- `M'
- Integer in the range 0 to 32
-
- `Q'
- A memory reference where the exact address is in a single
- register (``m'' is preferable for `asm' statements)
-
- `R'
- An item in the constant pool
-
- `S'
- A symbol in the text segment of the current file
-
-_AMD 29000 family--`a29k.h'_
-
- `l'
- Local register 0
-
- `b'
- Byte Pointer (`BP') register
-
- `q'
- `Q' register
-
- `h'
- Special purpose register
-
- `A'
- First accumulator register
-
- `a'
- Other accumulator register
-
- `f'
- Floating point register
-
- `I'
- Constant greater than 0, less than 0x100
-
- `J'
- Constant greater than 0, less than 0x10000
-
- `K'
- Constant whose high 24 bits are on (1)
-
- `L'
- 16-bit constant whose high 8 bits are on (1)
-
- `M'
- 32-bit constant whose high 16 bits are on (1)
-
- `N'
- 32-bit negative constant that fits in 8 bits
-
- `O'
- The constant 0x80000000 or, on the 29050, any 32-bit constant
- whose low 16 bits are 0.
-
- `P'
- 16-bit negative constant that fits in 8 bits
-
- `G'
- `H'
- A floating point constant (in `asm' statements, use the
- machine independent `E' or `F' instead)
-
-_AVR family--`avr.h'_
-
- `l'
- Registers from r0 to r15
-
- `a'
- Registers from r16 to r23
-
- `d'
- Registers from r16 to r31
-
- `w'
- Registers from r24 to r31. These registers can be used in
- `adiw' command
-
- `e'
- Pointer register (r26-r31)
-
- `b'
- Base pointer register (r28-r31)
-
- `q'
- Stack pointer register (SPH:SPL)
-
- `t'
- Temporary register r0
-
- `x'
- Register pair X (r27:r26)
-
- `y'
- Register pair Y (r29:r28)
-
- `z'
- Register pair Z (r31:r30)
-
- `I'
- Constant greater than -1, less than 64
-
- `J'
- Constant greater than -64, less than 1
-
- `K'
- Constant integer 2
-
- `L'
- Constant integer 0
-
- `M'
- Constant that fits in 8 bits
-
- `N'
- Constant integer -1
-
- `O'
- Constant integer 8, 16, or 24
-
- `P'
- Constant integer 1
-
- `G'
- A floating point constant 0.0
-
-_IBM RS6000--`rs6000.h'_
-
- `b'
- Address base register
-
- `f'
- Floating point register
-
- `h'
- `MQ', `CTR', or `LINK' register
-
- `q'
- `MQ' register
-
- `c'
- `CTR' register
-
- `l'
- `LINK' register
-
- `x'
- `CR' register (condition register) number 0
-
- `y'
- `CR' register (condition register)
-
- `z'
- `FPMEM' stack memory for FPR-GPR transfers
-
- `I'
- Signed 16-bit constant
-
- `J'
- Unsigned 16-bit constant shifted left 16 bits (use `L'
- instead for `SImode' constants)
-
- `K'
- Unsigned 16-bit constant
-
- `L'
- Signed 16-bit constant shifted left 16 bits
-
- `M'
- Constant larger than 31
-
- `N'
- Exact power of 2
-
- `O'
- Zero
-
- `P'
- Constant whose negation is a signed 16-bit constant
-
- `G'
- Floating point constant that can be loaded into a register
- with one instruction per word
-
- `Q'
- Memory operand that is an offset from a register (`m' is
- preferable for `asm' statements)
-
- `R'
- AIX TOC entry
-
- `S'
- Constant suitable as a 64-bit mask operand
-
- `T'
- Constant suitable as a 32-bit mask operand
-
- `U'
- System V Release 4 small data area reference
-
-_Intel 386--`i386.h'_
-
- `q'
- `a', `b', `c', or `d' register for the i386. For x86-64 it
- is equivalent to `r' class. (for 8-bit instructions that do
- not use upper halves)
-
- `Q'
- `a', `b', `c', or `d' register. (for 8-bit instructions, that
- do use upper halves)
-
- `R'
- Legacy register--equivalent to `r' class in i386 mode. (for
- non-8-bit registers used together with 8-bit upper halves in
- a single instruction)
-
- `A'
- Specifies the `a' or `d' registers. This is primarily useful
- for 64-bit integer values (when in 32-bit mode) intended to
- be returned with the `d' register holding the most
- significant bits and the `a' register holding the least
- significant bits.
-
- `f'
- Floating point register
-
- `t'
- First (top of stack) floating point register
-
- `u'
- Second floating point register
-
- `a'
- `a' register
-
- `b'
- `b' register
-
- `c'
- `c' register
-
- `d'
- `d' register
-
- `D'
- `di' register
-
- `S'
- `si' register
-
- `x'
- `xmm' SSE register
-
- `y'
- MMX register
-
- `I'
- Constant in range 0 to 31 (for 32-bit shifts)
-
- `J'
- Constant in range 0 to 63 (for 64-bit shifts)
-
- `K'
- `0xff'
-
- `L'
- `0xffff'
-
- `M'
- 0, 1, 2, or 3 (shifts for `lea' instruction)
-
- `N'
- Constant in range 0 to 255 (for `out' instruction)
-
- `Z'
- Constant in range 0 to `0xffffffff' or symbolic reference
- known to fit specified range. (for using immediates in zero
- extending 32-bit to 64-bit x86-64 instructions)
-
- `e'
- Constant in range -2147483648 to 2147483647 or symbolic
- reference known to fit specified range. (for using
- immediates in 64-bit x86-64 instructions)
-
- `G'
- Standard 80387 floating point constant
-
-_Intel 960--`i960.h'_
-
- `f'
- Floating point register (`fp0' to `fp3')
-
- `l'
- Local register (`r0' to `r15')
-
- `b'
- Global register (`g0' to `g15')
-
- `d'
- Any local or global register
-
- `I'
- Integers from 0 to 31
-
- `J'
- 0
-
- `K'
- Integers from -31 to 0
-
- `G'
- Floating point 0
-
- `H'
- Floating point 1
-
-_MIPS--`mips.h'_
-
- `d'
- General-purpose integer register
-
- `f'
- Floating-point register (if available)
-
- `h'
- `Hi' register
-
- `l'
- `Lo' register
-
- `x'
- `Hi' or `Lo' register
-
- `y'
- General-purpose integer register
-
- `z'
- Floating-point status register
-
- `I'
- Signed 16-bit constant (for arithmetic instructions)
-
- `J'
- Zero
-
- `K'
- Zero-extended 16-bit constant (for logic instructions)
-
- `L'
- Constant with low 16 bits zero (can be loaded with `lui')
-
- `M'
- 32-bit constant which requires two instructions to load (a
- constant which is not `I', `K', or `L')
-
- `N'
- Negative 16-bit constant
-
- `O'
- Exact power of two
-
- `P'
- Positive 16-bit constant
-
- `G'
- Floating point zero
-
- `Q'
- Memory reference that can be loaded with more than one
- instruction (`m' is preferable for `asm' statements)
-
- `R'
- Memory reference that can be loaded with one instruction (`m'
- is preferable for `asm' statements)
-
- `S'
- Memory reference in external OSF/rose PIC format (`m' is
- preferable for `asm' statements)
-
-_Motorola 680x0--`m68k.h'_
-
- `a'
- Address register
-
- `d'
- Data register
-
- `f'
- 68881 floating-point register, if available
-
- `x'
- Sun FPA (floating-point) register, if available
-
- `y'
- First 16 Sun FPA registers, if available
-
- `I'
- Integer in the range 1 to 8
-
- `J'
- 16-bit signed number
-
- `K'
- Signed number whose magnitude is greater than 0x80
-
- `L'
- Integer in the range -8 to -1
-
- `M'
- Signed number whose magnitude is greater than 0x100
-
- `G'
- Floating point constant that is not a 68881 constant
-
- `H'
- Floating point constant that can be used by Sun FPA
-
-_Motorola 68HC11 & 68HC12 families--`m68hc11.h'_
-
- `a'
- Register 'a'
-
- `b'
- Register 'b'
-
- `d'
- Register 'd'
-
- `q'
- An 8-bit register
-
- `t'
- Temporary soft register _.tmp
-
- `u'
- A soft register _.d1 to _.d31
-
- `w'
- Stack pointer register
-
- `x'
- Register 'x'
-
- `y'
- Register 'y'
-
- `z'
- Pseudo register 'z' (replaced by 'x' or 'y' at the end)
-
- `A'
- An address register: x, y or z
-
- `B'
- An address register: x or y
-
- `D'
- Register pair (x:d) to form a 32-bit value
-
- `L'
- Constants in the range -65536 to 65535
-
- `M'
- Constants whose 16-bit low part is zero
-
- `N'
- Constant integer 1 or -1
-
- `O'
- Constant integer 16
-
- `P'
- Constants in the range -8 to 2
-
-
-_SPARC--`sparc.h'_
-
- `f'
- Floating-point register that can hold 32- or 64-bit values.
-
- `e'
- Floating-point register that can hold 64- or 128-bit values.
-
- `I'
- Signed 13-bit constant
-
- `J'
- Zero
-
- `K'
- 32-bit constant with the low 12 bits clear (a constant that
- can be loaded with the `sethi' instruction)
-
- `L'
- A constant in the range supported by `movcc' instructions
-
- `M'
- A constant in the range supported by `movrcc' instructions
-
- `N'
- Same as `K', except that it verifies that bits that are not
- in the lower 32-bit range are all zero. Must be used instead
- of `K' for modes wider than `SImode'
-
- `G'
- Floating-point zero
-
- `H'
- Signed 13-bit constant, sign-extended to 32 or 64 bits
-
- `Q'
- Floating-point constant whose integral representation can be
- moved into an integer register using a single sethi
- instruction
-
- `R'
- Floating-point constant whose integral representation can be
- moved into an integer register using a single mov instruction
-
- `S'
- Floating-point constant whose integral representation can be
- moved into an integer register using a high/lo_sum
- instruction sequence
-
- `T'
- Memory address aligned to an 8-byte boundary
-
- `U'
- Even register
-
- `W'
- Memory address for `e' constraint registers.
-
-
-_TMS320C3x/C4x--`c4x.h'_
-
- `a'
- Auxiliary (address) register (ar0-ar7)
-
- `b'
- Stack pointer register (sp)
-
- `c'
- Standard (32-bit) precision integer register
-
- `f'
- Extended (40-bit) precision register (r0-r11)
-
- `k'
- Block count register (bk)
-
- `q'
- Extended (40-bit) precision low register (r0-r7)
-
- `t'
- Extended (40-bit) precision register (r0-r1)
-
- `u'
- Extended (40-bit) precision register (r2-r3)
-
- `v'
- Repeat count register (rc)
-
- `x'
- Index register (ir0-ir1)
-
- `y'
- Status (condition code) register (st)
-
- `z'
- Data page register (dp)
-
- `G'
- Floating-point zero
-
- `H'
- Immediate 16-bit floating-point constant
-
- `I'
- Signed 16-bit constant
-
- `J'
- Signed 8-bit constant
-
- `K'
- Signed 5-bit constant
-
- `L'
- Unsigned 16-bit constant
-
- `M'
- Unsigned 8-bit constant
-
- `N'
- Ones complement of unsigned 16-bit constant
-
- `O'
- High 16-bit constant (32-bit constant with 16 LSBs zero)
-
- `Q'
- Indirect memory reference with signed 8-bit or index register
- displacement
-
- `R'
- Indirect memory reference with unsigned 5-bit displacement
-
- `S'
- Indirect memory reference with 1 bit or index register
- displacement
-
- `T'
- Direct memory reference
-
- `U'
- Symbolic address
-
-
-_S/390 and zSeries--`s390.h'_
-
- `a'
- Address register (general purpose register except r0)
-
- `d'
- Data register (arbitrary general purpose register)
-
- `f'
- Floating-point register
-
- `I'
- Unsigned 8-bit constant (0-255)
-
- `J'
- Unsigned 12-bit constant (0-4095)
-
- `K'
- Signed 16-bit constant (-32768-32767)
-
- `L'
- Unsigned 16-bit constant (0-65535)
-
- `Q'
- Memory reference without index register
-
- `S'
- Symbolic constant suitable for use with the `larl' instruction
-
-
-_Xstormy16--`stormy16.h'_
-
- `a'
- Register r0.
-
- `b'
- Register r1.
-
- `c'
- Register r2.
-
- `d'
- Register r8.
-
- `e'
- Registers r0 through r7.
-
- `t'
- Registers r0 and r1.
-
- `y'
- The carry register.
-
- `z'
- Registers r8 and r9.
-
- `I'
- A constant between 0 and 3 inclusive.
-
- `J'
- A constant that has exactly one bit set.
-
- `K'
- A constant that has exactly one bit clear.
-
- `L'
- A constant between 0 and 255 inclusive.
-
- `M'
- A constant between -255 and 0 inclusive.
-
- `N'
- A constant between -3 and 0 inclusive.
-
- `O'
- A constant between 1 and 4 inclusive.
-
- `P'
- A constant between -4 and -1 inclusive.
-
- `Q'
- A memory reference that is a stack push.
-
- `R'
- A memory reference that is a stack pop.
-
- `S'
- A memory reference that refers to an constant address of
- known value.
-
- `T'
- The register indicated by Rx (not implemented yet).
-
- `U'
- A constant that is not between 2 and 15 inclusive.
-
-
-_Xtensa--`xtensa.h'_
-
- `a'
- General-purpose 32-bit register
-
- `b'
- One-bit boolean register
-
- `A'
- MAC16 40-bit accumulator register
-
- `I'
- Signed 12-bit integer constant, for use in MOVI instructions
-
- `J'
- Signed 8-bit integer constant, for use in ADDI instructions
-
- `K'
- Integer constant valid for BccI instructions
-
- `L'
- Unsigned constant valid for BccUI instructions
-
-
-
projects / msp430-gcc.git / blobdiff