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Stack Pointer: Difference between revisions
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The '''Stack Pointer''' on the [[SPC700]] is 16-bit, but the upper byte is fixed by the hardware to be 0x01. | The '''Stack Pointer''' (SP) on the [[SPC700]] is 16-bit, but the upper byte is fixed by the hardware to be 0x01. | ||
On the [[65c816]], the only two instructions that modify the stack pointer directly are [[TCS]] and [[TXS]]. It is only fixed to be in page one in [[emulation mode]] on the '816. | On the [[65c816]], the only two instructions that modify the stack pointer (S) directly are [[TCS]] and [[TXS]]. It is only fixed to be in page one in [[emulation mode]] on the '816. | ||
1FFh is a common value to initialize the stack pointer to. | 1FFh is a common value to initialize the stack pointer to. | ||
Revision as of 23:09, 22 July 2024
The Stack Pointer (SP) on the SPC700 is 16-bit, but the upper byte is fixed by the hardware to be 0x01.
On the 65c816, the only two instructions that modify the stack pointer (S) directly are TCS and TXS. It is only fixed to be in page one in emulation mode on the '816.
1FFh is a common value to initialize the stack pointer to.
See Also
References
- subparagraph 8.1.5 of page 3-8-4 of Book I of the official Super Nintendo development manual
- diversified activities: page 3-8-5 of Book I, lbid.
- Eyes & Lichty page 31, https://archive.org/details/0893037893ProgrammingThe65816/page/31