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| author | Tom Wood <wood@gnu.org> | 1992-08-25 20:13:49 +0000 |
|---|---|---|
| committer | Tom Wood <wood@gnu.org> | 1992-08-25 20:13:49 +0000 |
| commit | f6601f3af4096b593a7f010b17737b97747b9a46 (patch) | |
| tree | 7169641f3e222850367ccb206cf3d3bf84ff83a7 /gcc/rtl.def | |
| parent | 77472c5a50c8e78c3181e4da6fd457c0621b6f1b (diff) | |
| download | gcc-f6601f3af4096b593a7f010b17737b97747b9a46.tar.gz | |
entered into RCS
From-SVN: r1945
Diffstat (limited to 'gcc/rtl.def')
| -rw-r--r-- | gcc/rtl.def | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/gcc/rtl.def b/gcc/rtl.def index 17b9715de43..cdbfba6e34f 100644 --- a/gcc/rtl.def +++ b/gcc/rtl.def @@ -236,7 +236,7 @@ DEF_RTL_EXPR(DEFINE_DELAY, "define_delay", "eE", 'x') Each gives a set of operations and associated delays. The first three operands must be the same for each operation for the same function unit. - All delays are specified in units of COST_PER_CYCLE. + All delays are specified in cycles. 1st operand: Name of function unit (mostly for documentation) 2nd operand: Number of identical function units in CPU @@ -250,19 +250,21 @@ DEF_RTL_EXPR(DEFINE_DELAY, "define_delay", "eE", 'x') executing this operation. The meaning depends on whether or not the next operand is supplied. 7th operand: If this operand is not specified, the 6th operand gives the - cost of scheduling another operation on this unit while a - previous one is active. A value of zero should be used for a - pipelined unit. If only one operation can be executed a time - and the unit is busy for the entire time, the 3rd operand - should be specified as 1 and the 6th and 7th operands will - be ignored. + number of cycles after the instruction matching the 4th + operand begins using the function unit until a subsequent + insn can begin. A value of zero should be used for a + unit with no issue constraints. If only one operation can + be executed a time and the unit is busy for the entire time, + the 3rd operand should be specified as 1, the 6th operand + sould be specified as 0, and the 7th operand should not + be specified. If this operand is specified, it is a list of attribute expressions. If an insn for which any of these expressions is true is currently executing on the function unit, the - delay will be given by the 6th operand. Otherwise, the - insn can be immediately scheduled (subject to the limit on - the number of simultaneous operations executing on the + issue delay will be given by the 6th operand. Otherwise, + the insn can be immediately scheduled (subject to the limit + on the number of simultaneous operations executing on the unit.) */ DEF_RTL_EXPR(DEFINE_FUNCTION_UNIT, "define_function_unit", "siieiiV", 'x') |