CISCO IE-4000-16GT4G-E工業交換機,用戶手冊
保持調試器運行環境
本節介紹了如何避免污染操作系統調試器的環境。涵蓋的主題包括：
? 187Bug向量表和工作空間? 硬件功能
? 187Bug使用的異常向量? CPU/MPU寄存器
187Bug使用某些MVME187板載資源，并且可能也可以使用非車載系統內存來包含臨時變量，異常向量，等等，如果你干擾了你所依賴的資源則調試器的功能可能不可靠或根本不起作用。
CISCO IE-4000-16GT4G-E工業交換機如果應用程序允許通過內存進行翻譯管理單元（MMU），并利用調試器的資源（例如，系統調用），應用程序必須創建必要的調試器訪問其各種資源。調試器支持MMU的啟用；確實如此不禁用翻譯。187Bug向量表和工作空間調試器和診斷固件位于EPROM中。這個調試器還使用前64KB的RAM存儲向量表、可執行代碼、變量和堆棧。硬件功能調試器使用的唯一硬件資源是EIA232-D端口，這些端口初始化為與調試終端接口還有一個主持人。如果對這些端口重新編程，則終端必須修改特性以適應，否則端口應在重新調用之前還原到調試器集特征調試器。
注意，盡管187Bug沒有明確管理MC88200或MC88204 CMMU，硬件防止在MVME187上緩存輸入/輸出空間，即。，$FFFXXXXX。此外，代碼緩存不得可用于正在跟蹤的代碼頁或已中斷。187Bug使用的異常向量前16個MC88100異常向量（即#496到511）保留供調試器使用。
Preserving the Debugger Operating
Environment
This section explains how to avoid contaminating the operating
environment of the debugger. Topics covered include:
? 187Bug Vector Table and workspace
? Hardware functions
? Exception vectors used by 187Bug
? CPU/MPU registers
187Bug uses certain of the MVME187 onboard resources and may
also use offboard system memory to contain temporary variables,
exception vectors, etc. If you disturb resources upon which 187Bug
depends, then the debugger may function unreliably or not at all.
If your application enables translation through the Memory
Management Units (MMUs), and utilizes resources of the debugger
(e.g., system calls), your application must create the necessary
translation tables for the debugger to have access to its various
resources. The debugger honors the enabling of the MMUs; it does
not disable translation.
187Bug Vector Table and Workspace
The debugger and diagnostic firmware resides in the EPROMs. The
first 64KB of RAM are also used by the debugger for storage of the
Vector Table, executable code, variables, and stack. Hardware Functions
The only hardware resources used by the debugger are the EIA232-D ports, which are initialized to interface to the debug terminal
and a host. If these ports are reprogrammed, the terminal
characteristics must be modified to suit, or the ports should be
restored to the debugger-set characteristics prior to reinvoking the
debugger.
Note Although the 187Bug does not explicitly manage the
MC88200 or MC88204 CMMUs, hardware prevents
caching of I/O space on the MVME187, i.e.,
$FFFXXXXX. Furthermore, the code cache must not be
operative for code pages which are being traced or
breakpointed.
Exception Vectors Used by 187Bug
The top 16 MC88100 exception vectors (i.e., #496 to 511 inclusive)
are reserved for use by the debugger
