We've just updated MediaWiki and its underlying software. If anything doesn't look or work quite right, please mention it to us. --RanAS
Stack Pointer: Difference between revisions
From SnesLab
(abbreviations) |
(added ref) |
||
| Line 1: | Line 1: | ||
The '''Stack Pointer''' (SP) 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 (S) 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]].<sup>[4]</sup> 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. | ||
| Line 12: | Line 12: | ||
=== References === | === References === | ||
# subparagraph 8.1.5 of [https://archive.org/details/SNESDevManual/book1/page/n182 page 3-8-4 of Book I] of the official Super Nintendo development manual | |||
# diversified activities: [https://archive.org/details/SNESDevManual/book1/page/n183 page 3-8-5 of Book I], lbid. | |||
# [[Eyes & Lichty]] page 31, https://archive.org/details/0893037893ProgrammingThe65816/page/31 | |||
# [[Eyes & Lichty]] page 511, on TCS: https://archive.org/details/0893037893ProgrammingThe65816/page/511 | |||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:Registers]] | [[Category:Registers]] | ||
[[Category:Inherited from 6502]] | [[Category:Inherited from 6502]] | ||
Revision as of 23:13, 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.[4] 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
- Eyes & Lichty page 511, on TCS: https://archive.org/details/0893037893ProgrammingThe65816/page/511