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Eliminated block size constraints, added support for bit fields

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This commit is contained in:
Jeff Parsons 2015-04-27 18:26:54 -07:00 • committed by jeffpar
commit bf8148611d
6 changed files with 341 additions and 212 deletions
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34
modules/pcjs/lib/defines.js
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@ -82,16 +82,16 @@ var TYPEDARRAYS = (typeof ArrayBuffer !== 'undefined');
/**
* @define {boolean}
*
* Enables backtracking (disabled in compiled versions). Backtracking is a mechanism that allows us to tag
* every byte of incoming data and follow the flow of that data.
* BACKTRACK enables backtracking (disabled in compiled versions). Backtracking is a mechanism that allows
* us to tag every byte of incoming data and follow the flow of that data.
*/
var BACKTRACK = !COMPILED;
/**
* @define {boolean}
*
* Enables instruction sampling (a work-in-progress). This was used briefly as an internal debugging aid, to
* periodically record LIP values in a fixed-length sampling buffer, halting execution once the sampling buffer
* SAMPLER enables instruction sampling (a work-in-progress). This was used briefly as an internal debugging aid,
* to periodically record LIP values in a fixed-length sampling buffer, halting execution once the sampling buffer
* was full, and then compare those sampled LIP values to corresponding LIP values on subsequent runs, to look
* for deviations. In theory, every run is supposed to be absolutely identical, even if you interrupt execution
* with the Debugger or enable/disable different sets of messages, but in practice, that's hard to guarantee.
@ -101,9 +101,9 @@ var SAMPLER = false;
/**
* @define {boolean}
*
* Enables support for known 8086 bugs. It's turned off by default, because 1) it adds overhead, and 2) it's
* hard to imagine any software actually being dependent on any of the bugs covered by this (eg, the failure to
* properly restart string instructions with multiple prefixes, or the failure to inhibit hardware interrupts
* BUGS_8086 enables support for known 8086 bugs. It's turned off by default, because 1) it adds overhead, and
* 2) it's hard to imagine any software actually being dependent on any of the bugs covered by this (eg, the failure
* to properly restart string instructions with multiple prefixes, or the failure to inhibit hardware interrupts
* following SS segment loads).
*/
var BUGS_8086 = false;
@ -111,19 +111,33 @@ var BUGS_8086 = false;
/**
* @define {boolean}
*
* Enables 80386 support. My preference continues to be one "binary" that supports all implemented CPUs, but
* I386 enables 80386 support. My preference continues to be one "binary" that supports all implemented CPUs, but
* I'm providing this to enable a slimmed-down binary, at least until 80386 support is actually finished; at the
* moment, there's just a lot of scaffolding that bloats the compiled version without adding real functionality.
* moment, there's just a lot of scaffolding that bloats the compiled version without adding any real functionality.
*/
var I386 = true;
/**
* @define {boolean}
*
* Enables Compaq DeskPro 386 support.
* COMPAQ386 enables Compaq DeskPro 386 support.
*/
var COMPAQ386 = true;
/**
* @define {boolean}
*
* PAGEBLOCKS enables 80386 paging support with assistance from the Bus component. This affects how the Bus component
* defines physical memory parameters for a 32-bit bus. With the 8086 and 80286 processors, the Bus component was free
* to choose any block size for physical memory allocations that made sense for the bus width (eg, 4Kb blocks for a
* 20-bit bus, or 16Kb blocks for 24-bit bus).
*
* However, for the 80386 processor, it makes more sense to choose a block size that matches the page size (ie, 4Kb),
* because then we have the option of altering the address-to-memory mapping for any block to match whatever page table
* mapping is in effect for that address, if any, without requiring another layer of address translation.
*/
var PAGEBLOCKS = I386;
if (typeof module !== 'undefined') {
global.PCJSCLASS = PCJSCLASS;
global.DEBUGGER = DEBUGGER;