diff options
Diffstat (limited to 'gcc/doc/rtl.texi')
| -rw-r--r-- | gcc/doc/rtl.texi | 50 |
1 files changed, 25 insertions, 25 deletions
diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi index d3f50d0c233..f84dfadea35 100644 --- a/gcc/doc/rtl.texi +++ b/gcc/doc/rtl.texi @@ -1,4 +1,4 @@ -@c Copyright (C) 1988, 1989, 1992, 1994, 1997, 1998, 1999, 2000, 2001, 2002, 2003 +@c Copyright (C) 1988, 1989, 1992, 1994, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 @c Free Software Foundation, Inc. @c This is part of the GCC manual. @c For copying conditions, see the file gcc.texi. @@ -308,16 +308,16 @@ Operands of expressions are accessed using the macros @code{XEXP}, two arguments: an expression-pointer (RTX) and an operand number (counting from zero). Thus, -@example +@smallexample XEXP (@var{x}, 2) -@end example +@end smallexample @noindent accesses operand 2 of expression @var{x}, as an expression. -@example +@smallexample XINT (@var{x}, 2) -@end example +@end smallexample @noindent accesses the same operand as an integer. @code{XSTR}, used in the same @@ -1850,9 +1850,9 @@ Represents the signed product of the values represented by @var{x} and Some machines support a multiplication that generates a product wider than the operands. Write the pattern for this as -@example +@smallexample (mult:@var{m} (sign_extend:@var{m} @var{x}) (sign_extend:@var{m} @var{y})) -@end example +@end smallexample where @var{m} is wider than the modes of @var{x} and @var{y}, which need not be the same. @@ -1874,9 +1874,9 @@ Some machines have division instructions in which the operands and quotient widths are not all the same; you should represent such instructions using @code{truncate} and @code{sign_extend} as in, -@example +@smallexample (truncate:@var{m1} (div:@var{m2} @var{x} (sign_extend:@var{m2} @var{y}))) -@end example +@end smallexample @findex udiv @cindex unsigned division @@ -2232,9 +2232,9 @@ operation requires two operands of the same machine mode. Therefore, the byte-sized operand is enclosed in a conversion operation, as in -@example +@smallexample (plus:SI (sign_extend:SI (reg:QI 34)) (reg:SI 80)) -@end example +@end smallexample The conversion operation is not a mere placeholder, because there may be more than one way of converting from a given starting mode @@ -2567,10 +2567,10 @@ side effect expressions---expressions of code @code{set}, @code{call}, side-effects are computed, and second all the actual side-effects are performed. For example, -@example +@smallexample (parallel [(set (reg:SI 1) (mem:SI (reg:SI 1))) (set (mem:SI (reg:SI 1)) (reg:SI 1))]) -@end example +@end smallexample @noindent says unambiguously that the values of hard register 1 and the memory @@ -2583,13 +2583,13 @@ expect the result of one @code{set} to be available for the next one. For example, people sometimes attempt to represent a jump-if-zero instruction this way: -@example +@smallexample (parallel [(set (cc0) (reg:SI 34)) (set (pc) (if_then_else (eq (cc0) (const_int 0)) (label_ref @dots{}) (pc)))]) -@end example +@end smallexample @noindent But this is incorrect, because it says that the jump condition depends @@ -2716,9 +2716,9 @@ by is the length in bytes of the machine mode of the containing memory reference of which this expression serves as the address. Here is an example of its use: -@example +@smallexample (mem:DF (pre_dec:SI (reg:SI 39))) -@end example +@end smallexample @noindent This says to decrement pseudo register 39 by the length of a @code{DFmode} @@ -2878,16 +2878,16 @@ chain delimited by these insns, the @code{NEXT_INSN} and @code{PREV_INSN} pointers must always correspond: if @var{insn} is not the first insn, -@example +@smallexample NEXT_INSN (PREV_INSN (@var{insn})) == @var{insn} -@end example +@end smallexample @noindent is always true and if @var{insn} is not the last insn, -@example +@smallexample PREV_INSN (NEXT_INSN (@var{insn})) == @var{insn} -@end example +@end smallexample @noindent is always true. @@ -3459,9 +3459,9 @@ RTL expression code, @code{call}. @cindex @code{call} usage A @code{call} expression has two operands, as follows: -@example +@smallexample (call (mem:@var{fm} @var{addr}) @var{nbytes}) -@end example +@end smallexample @noindent Here @var{nbytes} is an operand that represents the number of bytes of @@ -3479,10 +3479,10 @@ For a subroutine that returns a value whose mode is not @code{BLKmode}, the value is returned in a hard register. If this register's number is @var{r}, then the body of the call insn looks like this: -@example +@smallexample (set (reg:@var{m} @var{r}) (call (mem:@var{fm} @var{addr}) @var{nbytes})) -@end example +@end smallexample @noindent This RTL expression makes it clear (to the optimizer passes) that the |
