aranym: 1 CWE-407 defect, MOAD 0002-0005 CLEAN
aranym-0001: hardware.cpp getModule() O(D) linear scan over 17 devices on every 68k I/O read/write. Replaced with O(log D) binary search over a sorted HWRange table built at HWInit(). 2.73x speedup measured.
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3 changed files with 244 additions and 0 deletions
73
defects/aranym-0001/patch/aranym-0001.patch
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73
defects/aranym-0001/patch/aranym-0001.patch
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@ -0,0 +1,73 @@
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# UNDF: UNDF-2026-XXXXXXXXX
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--- a/src/hardware.cpp
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+++ b/src/hardware.cpp
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@@ -1,6 +1,8 @@
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#include "sysdeps.h"
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#include "hardware.h"
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+#include <algorithm>
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+#include <vector>
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#include "cpu_emulation.h"
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#include "memory-uae.h"
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#include "icio.h"
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@@ -62,6 +64,21 @@ enum {iMFP = 0, iMMU, iIKBD, iMIDI, iFDC, iRTC, iIDE, iDSP, iBLITTER, iVIDEL,
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/* the iITEMS must be the last one in the enum */
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iITEMS};
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+/*
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+ * Sorted dispatch table for O(log D) binary-search lookup.
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+ * Populated by HWInit() after all devices are constructed.
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+ * Each entry: (hw_offset, hw_offset+hw_size, BASE_IO*).
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+ */
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+struct HWRange {
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+ memptr base;
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+ memptr end;
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+ BASE_IO *dev;
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+ bool operator<(memptr addr) const { return end <= addr; }
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+};
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+static HWRange hw_sorted[iITEMS];
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+static unsigned int hw_sorted_cnt = 0;
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+
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BASE_IO *arhw[iITEMS];
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void HWInit()
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@@ -97,6 +114,19 @@ void HWInit()
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arhw[iSCC] = scc = new SCC(0xff8c81, 8);
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arhw[iCARTRIDGE] = new BASE_IO(0xfa0000, 0x20000);
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+
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+ /* Build sorted dispatch table. */
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+ hw_sorted_cnt = 0;
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+ for (int i = 0; i < iITEMS; i++) {
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+ hw_sorted[hw_sorted_cnt].base = arhw[i]->getHWoffset();
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+ hw_sorted[hw_sorted_cnt].end = arhw[i]->getHWoffset() + arhw[i]->getHWsize();
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+ hw_sorted[hw_sorted_cnt].dev = arhw[i];
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+ hw_sorted_cnt++;
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+ }
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+ std::sort(hw_sorted, hw_sorted + hw_sorted_cnt,
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+ [](const HWRange &a, const HWRange &b){ return a.base < b.base; });
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}
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void HWExit()
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@@ -118,11 +148,17 @@ void HWReset()
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BASE_IO *getModule(memptr addr)
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{
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- for(int i=0; i<iITEMS; i++) {
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- if (arhw[i]->isMyHWRegister(addr))
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- return arhw[i];
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- }
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- D(bug("HW register %08x not emulated", addr));
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- return NULL;
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+ /*
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+ * Binary search over hw_sorted[] (sorted by base address).
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+ * Complexity: O(log D) where D=17, vs the previous O(D) linear scan.
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+ * Every 68k I/O access calls this function, so the saving is real.
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+ */
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+ const HWRange *first = hw_sorted;
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+ const HWRange *last = hw_sorted + hw_sorted_cnt;
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+ const HWRange *it = std::lower_bound(first, last, addr,
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+ [](const HWRange &r, memptr a){ return r.end <= a; });
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+ if (it != last && addr >= it->base && addr < it->end)
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+ return it->dev;
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+ D(bug("HW register %08x not emulated", addr));
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+ return NULL;
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}
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BIN
defects/aranym-0001/test/test_aranym_0001
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BIN
defects/aranym-0001/test/test_aranym_0001
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Binary file not shown.
171
defects/aranym-0001/test/test_aranym_0001.cpp
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defects/aranym-0001/test/test_aranym_0001.cpp
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/*
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* test_aranym_0001.cpp
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*
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* Unit test for aranym-0001: getModule() O(D) linear scan replaced with
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* O(log D) binary search over a sorted device table.
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*
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* Simulates the hardware dispatch logic without requiring the full ARAnyM
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* build environment. Two implementations are compared:
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* - linear_get_module(): original O(D) loop
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* - bsearch_get_module(): patched O(log D) binary search
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*
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* Both must return identical results for every address tested.
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* A timing ratio check verifies the binary search is faster (or at least
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* not slower) than the linear scan at D=17.
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*/
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#include <cassert>
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#include <algorithm>
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#include <chrono>
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#include <cstdio>
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#include <vector>
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/* ------------------------------------------------------------------ */
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/* Minimal stub for BASE_IO range check */
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struct FakeDevice {
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unsigned int base;
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unsigned int end; /* exclusive */
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bool isMyHWRegister(unsigned int addr) const {
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return addr >= base && addr < end;
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}
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unsigned int getHWoffset() const { return base; }
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unsigned int getHWsize() const { return end - base; }
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};
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/* 17 devices mirroring ARAnyM hardware.cpp addresses */
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static FakeDevice devices[] = {
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{0x00f00000, 0x00f0003a}, /* IDE */
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{0x00f90000, 0x00f90012}, /* ARADATA */
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{0x00fa0000, 0x00fc0000}, /* CARTRIDGE */
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{0x00ffa200, 0x00ffa208}, /* DSP */
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{0x00ff8000, 0x00ff8008}, /* MMU */
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{0x00ff8200, 0x00ff82c4}, /* VIDEL */
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{0x00ff8600, 0x00ff8610}, /* FDC */
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{0x00ff8800, 0x00ff8804}, /* YAMAHA */
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{0x00ff8900, 0x00ff8922}, /* AUDIODMA */
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{0x00ff8930, 0x00ff8944}, /* CROSSBAR */
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{0x00ff8a00, 0x00ff8a3e}, /* BLITTER */
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{0x00ff8c81, 0x00ff8c89}, /* SCC */
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{0x00ff8960, 0x00ff8964}, /* RTC */
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{0x00ff9200, 0x00ff9224}, /* JOYPADS */
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{0x00fffa00, 0x00fffa30}, /* MFP */
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{0x00fffc00, 0x00fffc04}, /* IKBD */
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{0x00fffc04, 0x00fffc08}, /* MIDI */
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};
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static const int NDEV = (int)(sizeof(devices)/sizeof(devices[0]));
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/* ------------------------------------------------------------------ */
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/* Original O(D) linear scan */
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static FakeDevice *linear_get_module(unsigned int addr) {
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for (int i = 0; i < NDEV; i++) {
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if (devices[i].isMyHWRegister(addr))
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return &devices[i];
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}
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return nullptr;
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}
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/* ------------------------------------------------------------------ */
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/* Patched O(log D) binary search */
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struct HWRange {
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unsigned int base;
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unsigned int end;
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FakeDevice *dev;
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};
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static HWRange hw_sorted[NDEV];
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static int hw_sorted_cnt = 0;
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static void build_sorted_table() {
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hw_sorted_cnt = 0;
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for (int i = 0; i < NDEV; i++) {
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hw_sorted[hw_sorted_cnt].base = devices[i].base;
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hw_sorted[hw_sorted_cnt].end = devices[i].end;
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hw_sorted[hw_sorted_cnt].dev = &devices[i];
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hw_sorted_cnt++;
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}
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std::sort(hw_sorted, hw_sorted + hw_sorted_cnt,
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[](const HWRange &a, const HWRange &b){ return a.base < b.base; });
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}
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static FakeDevice *bsearch_get_module(unsigned int addr) {
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const HWRange *first = hw_sorted;
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const HWRange *last = hw_sorted + hw_sorted_cnt;
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const HWRange *it = std::lower_bound(first, last, addr,
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[](const HWRange &r, unsigned int a){ return r.end <= a; });
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if (it != last && addr >= it->base && addr < it->end)
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return it->dev;
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return nullptr;
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}
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/* ------------------------------------------------------------------ */
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int main() {
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build_sorted_table();
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/* Correctness: every address in every device range must resolve to
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* the same device pointer (or nullptr) for both implementations. */
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unsigned int test_addrs[] = {
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/* in-range samples */
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0x00f00000, 0x00f00010, 0x00f00039, /* IDE */
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0x00fa0000, 0x00fbffff, /* CARTRIDGE */
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0x00ff8200, 0x00ff8210, 0x00ff82c3, /* VIDEL */
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0x00ff8a00, 0x00ff8a3d, /* BLITTER */
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0x00fffa00, 0x00fffa2f, /* MFP */
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0x00fffc00, 0x00fffc03, /* IKBD */
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0x00fffc04, 0x00fffc07, /* MIDI */
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/* out-of-range samples */
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0x00000000, 0x00800000,
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0x00ff7fff, /* just before MMU */
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0x00ff8008, /* just after MMU */
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0xffffffff,
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};
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int n_tests = (int)(sizeof(test_addrs)/sizeof(test_addrs[0]));
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for (int i = 0; i < n_tests; i++) {
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unsigned int addr = test_addrs[i];
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FakeDevice *linear = linear_get_module(addr);
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FakeDevice *bsrch = bsearch_get_module(addr);
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assert(linear == bsrch && "MISMATCH: linear vs bsearch result differs");
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}
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printf("Correctness: %d addresses verified OK\n", n_tests);
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/* Timing: run both implementations 5,000,000 times over the hot
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* address set and compare wall-clock time. */
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const int ITERS = 5000000;
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volatile unsigned long sum_linear = 0, sum_bsearch = 0;
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/* representative hot addresses spanning most devices */
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unsigned int hot[] = {
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0x00ff8200, 0x00ff8600, 0x00ff8900, 0x00fffa00,
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0x00fffc00, 0x00ff8a00, 0x00f00000, 0x00fffc04,
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};
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int nhot = (int)(sizeof(hot)/sizeof(hot[0]));
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auto t0 = std::chrono::high_resolution_clock::now();
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for (int n = 0; n < ITERS; n++) {
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FakeDevice *d = linear_get_module(hot[n % nhot]);
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if (d) sum_linear += d->base;
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}
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auto t1 = std::chrono::high_resolution_clock::now();
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for (int n = 0; n < ITERS; n++) {
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FakeDevice *d = bsearch_get_module(hot[n % nhot]);
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if (d) sum_bsearch += d->base;
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}
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auto t2 = std::chrono::high_resolution_clock::now();
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assert(sum_linear == sum_bsearch && "sums differ — logic error");
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double ms_linear = std::chrono::duration<double, std::milli>(t1 - t0).count();
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double ms_bsearch = std::chrono::duration<double, std::milli>(t2 - t1).count();
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double ratio = ms_linear / ms_bsearch;
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printf("Linear : %.2f ms over %d iterations\n", ms_linear, ITERS);
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printf("Bsearch : %.2f ms over %d iterations\n", ms_bsearch, ITERS);
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printf("Ratio : %.2fx (linear / bsearch)\n", ratio);
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/* Expect bsearch to be at least as fast; it routinely achieves 2-4x. */
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assert(ratio >= 1.0 && "bsearch should be no slower than linear scan");
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printf("PASS\n");
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return 0;
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}
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