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Limited Debug register support

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This commit is contained in:
Jeff Parsons 2015-08-02 21:11:19 -07:00
commit 9fa2941394
7 changed files with 168 additions and 85 deletions
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19
modules/pcjs/lib/memory.js
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@ -108,7 +108,7 @@ function Memory(addr, used, size, type, controller, cpu)
this.type = type || Memory.TYPE.NONE;
this.fReadOnly = (type == Memory.TYPE.ROM);
this.controller = null;
this.cpu = cpu;
this.cpu = cpu; // If a CPU reference is provided, then this must be an UNPAGED Memory block allocation
this.fDirty = this.fDirtyEver = false;
this.setPhysBlock();
@ -490,6 +490,8 @@ Memory.prototype = {
/**
* getPageBlock(addr, fWrite)
*
* Called for UNPAGED Memory blocks only.
*
* @this {Memory}
* @param {number} addr
* @param {boolean} fWrite (true if called for a write, false if for a read)
@ -526,7 +528,7 @@ Memory.prototype = {
*
* NOTE: Some Memory blocks already require access to the CPU (eg, UNPAGED blocks that need to call cpu.mapPageBlock()),
* while others require access only if the CPU has set a read or write breakpoint in one of its Debug registers; the latter
* case is handled here by virtue of the cpu parameter.
* case is handled here by virtue of the CPU parameter.
*
* @this {Memory}
* @param {number} off
@ -552,9 +554,15 @@ Memory.prototype = {
/**
* removeBreakpoint(off, fWrite)
*
* NOTE: If this Memory block is not an UNPAGED block that might need to call cpu.mapPageBlock()), and it no longer
* has any read or write breakpoints associated with it, then it no longer needs a CPU reference. However, the latter
* is a moot point, because the "checked" memory access functions should be swapped out when this function is done.
* NOTE: If this Memory block is not an UNPAGED block that might need to call cpu.mapPageBlock()), and it no
* longer has any read or write breakpoints associated with it, then it no longer needs a CPU reference. The
* existence of a CPU reference only impacts the performance of the "checked" memory access functions, so it's
* not critical to eliminate it, but we do it anyway, in case the "checked" functions become re-enabled later
* (eg, by the Debugger -- yeah, the Debugger, which is why eliminating it isn't critical).
*
* TODO: Another option would be to count CPU references separately from Debugger references, so that when the
* former goes to zero, we can unconditionally remove the CPU reference; UNPAGED blocks would automatically
* increment that reference count, so their CPU reference would never go away.
*
* @this {Memory}
* @param {number} off
@ -575,6 +583,7 @@ Memory.prototype = {
}
Component.assert(this.cWriteBreakpoints >= 0);
}
if (!this.cReadBreakpoints && !this.cWriteBreakpoints && this.type != Memory.TYPE.UNPAGED) this.cpu = null;
},
/**
* readNone(off)