PCDVD數位科技討論區 - 瀏覽單個文章 - 債務沉重超微半導體恐破產

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作者flatmode

拜託, xx bit cpu 跟定址完全沒關係, 通用指令暫存器的位寬是指檔案跟指令能被執行的寬度, 64bit 就是一次能再一個指令周期內在其中一個暫存器儲存64bit的資料而暫存器位寬是對照整數執行單元. 同架構下(指同樣數量的解碼器跟執行單元下)更多位元寬與更多暫存器會大大增加效能. 跟定址無關, 定址是指一顆processor能認得的記憶體大小. 現代消費級x86-64 cpu已經有十年是停在40 bit, 大約是1TB左右的可確認記憶體, 難道就是40bit cpu?? SNES超任能定址到32bit, 可是SNES卻是只有8bit暫存器跟8 bit 整數執行單元, 難道SNES就是32位元主機嗎?? 給你科普一下.....

映像中 SNES 不是 16位元主機嗎??
剛剛去查了一下,
從這裡 https://en.wikibooks.org/wiki/Super...5c816_reference
查到 65816 Primer http://softpixel.com/~cwright/sianse/docs/65816NFO.HTM

======================================
3.10 Native Mode Registers
======================================

3.11 Accumulator
-----------------

Although shown as a 16 bit register, it may be either 16 or 8 depending on the status of bit 5 (memory/accumulator select) of the status register bit designated M.

When in 8 bit mode (M=1) then the accessible low order 8 bit accumulator is designated as A and the hidden but exchangeable is designated B. When in full 16 bit accumulator mode (M=0) then the accumulator is designated as C.