fix early cast when calculating cache size

[haochengxia]

Fix #300

[gemini-code-assist]

Summary of Changes

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This pull request addresses a critical bug where cache sub-component sizes were being miscalculated due to premature type casting, potentially leading to incorrect cache behavior. By adjusting the order of operations and adding robust validation, the changes ensure accurate cache sizing and prevent the system from operating with invalid or zero-sized cache partitions, thereby improving the overall stability and reliability of the cache simulation framework.

Highlights

• Bug Fix: Early Type Casting: Corrected an 'early cast' bug in cache size calculations across various eviction policies (ClockPro, QDLP, S3FIFO, S3FIFOd, S3FIFOv0, SLRU, S3LRU, flashProb). Previously, an int64_t cast was applied before multiplication or division with floating-point ratios, which could lead to precision loss and incorrect cache size determinations. The fix ensures that the floating-point arithmetic is completed before the final cast to int64_t.
• Cache Size Validation: Introduced validation checks in several cache initialization functions (QDLP, S3FIFO, S3FIFOd, S3FIFOv0, SLRU, S3LRU, flashProb) to ensure that calculated sub-cache sizes (e.g., FIFO, main, LRU, RAM, disk segments) are positive. If a calculated size is zero or negative, an ERROR message is now logged, preventing the creation of invalid cache configurations.

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[gemini-code-assist]

Code Review

This pull request correctly fixes a critical bug across multiple cache eviction algorithm implementations where an early cast from uint64_t to int64_t could lead to integer overflow when calculating cache partition sizes. The fix involves changing the order of operations to perform floating-point multiplication or integer division before casting to int64_t, which prevents the overflow. Additionally, the PR introduces valuable validation checks to ensure that calculated cache and segment sizes are positive, aborting with a descriptive error message on invalid configurations. These changes significantly improve the robustness and correctness of the cache size calculations.