VHDL数据类型BIT、INTEGER和BOOLEAN分别定义在哪个库中？哪些库和程序包总是可见的？

VHDL数据类型BIT、INTEGER和BOOLEAN分别定义在哪个库中？哪些库和程序包总是可见的？

你是用Altera Maxplus II或Quartus II的话,应该在standard.vhd库中

对Maxplus,目录是在altera\maxplus2\vhdl93\std\standard.vhd, 如果是Quartus II的话,你自己搜索一下吧.

package STANDARD is

-- Predefined enumeration types

type BOOLEAN is (FALSE, TRUE);

type BIT is ('0', '1');

type CHARACTER IS (
NUL, SOH, STX, ETX, EOT, ENQ, ACK, BEL,
BS, HT, LF, VT, FF, CR, SO, SI,
DLE, DC1, DC2, DC3, DC4, NAK, SYN, ETB,
CAN, EM, SUB, ESC, FSP, GSP, RSP, USP,

' ', '!', '"', '#', '$', '%', '&', ''',
'(', ')', '*', '+', ',', '-', '.', '/',
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', ':', ';', '<', '=', '>', '?',

'@', 'A', 'B', 'C', 'D', 'E', 'F', 'G',
'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
'X', 'Y', 'Z',' '[', '\', ']', '^', '_',

'`', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
'x', 'y', 'z',' '{', '|', '}', '~', DEL,

C128, C129, C130, C131, C132, C133, C134, C135,
C136, C137, C138, C139, C140, C141, C142, C143,
C144, C145, C146, C147, C148, C149, C150, C151,
C152, C153, C154, C155, C156, C157, C158, C159,

'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',

'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',

'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?',
'?', '?', '?', '?', '?', '?', '?', '?');

type SEVERITY_LEVEL is (NOTE, WARNING, ERROR, FAILURE);

-- Predefined numeric types

type INTEGER is range -2147483648 to 2147483647;

type REAL is range -1.7e38 to 1.7e38;

-- Predefined type TIME

type TIME is range -9223372036854775808 to 9223372036854775807
units
fs; -- femtosecond
ps = 1000 fs; -- picosecond
ns = 1000 ps; -- nanosecond
us = 1000 ns; -- microsecond
ms = 1000 us; -- millisecond
sec = 1000 ms; -- second
min = 60 sec; -- minute
hr = 60 min; -- hour
end units;

subtype DELAY_LENGTH is TIME range 0 fs to TIME'HIGH;

-- A function that returns the current simulation time, Tc (see Section 12.6.4):

impure function NOW return DELAY_LENGTH;

-- Predefined numeric subtypes:

subtype NATURAL is INTEGER range 0 to INTEGER'HIGH;

subtype POSITIVE is INTEGER range 1 to INTEGER'HIGH;

-- Predefined array types:

type STRING is array (POSITIVE range <>) of CHARACTER;

type BIT_VECTOR is array (NATURAL range <>) of BIT;

-- The predefined types for opening files:

type FILE_OPEN_KIND is (
READ_MODE, -- Resulting access mode is read-only.
WRITE_MODE, -- Resulting access mode is write-only.
APPEND_MODE); -- Resulting access mode is write-only; information
-- is appended to the end of the existing file.

type FILE_OPEN_STATUS is (
OPEN_OK, -- File open was successful.
STATUS_ERROR, -- File object was already open.
NAME_ERROR, -- External file not found or inaccessible.
MODE_ERROR); -- Could not open file with requested access mode.

-- The 'FOREIGN attribute:

attribute FOREIGN: STRING;

end STANDARD;