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TCALL (SPC700): Difference between revisions
From SnesLab
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{| class="wikitable" style="float:right;clear:right;width: | {| class="wikitable" style="float:right;clear:right;width:50%" | ||
!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
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|'''Length''' | |'''Length''' | ||
|'''Speed''' | |'''Speed''' | ||
|''' | |'''Vector Address''' | ||
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|[[Implied]] (type 3) | |[[Implied]] (type 3) | ||
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'''TCALL''' (Table CALl) is an [[SPC700]] instruction that calls a subroutine in the [[uppermost page]]. The low byte of the | '''TCALL''' (Table CALl) is an [[SPC700]] instruction that calls a subroutine whose 16-bit address is stored in the [[uppermost page]]. The low byte of the address of the vector (pointer to subroutine) is a function of the high nybble of the opcode, equal to $DE - n*2. The high byte of the vector address is always $FF. | ||
No flags are affected. | No flags are affected. | ||
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</pre> | </pre> | ||
where n is decimal integer from 0 to 15, which becomes the high | where n is the '''vector call number''', a decimal integer from 0 to 15, which becomes the high nybble of the opcode. | ||
=== See Also === | === See Also === | ||
* [[CALL]] | * [[CALL]] | ||
* [[PCALL]] | * [[PCALL]] | ||
* [[RET]] | |||
* [[SPC700/IPL ROM]] | |||
=== External Links === | === External Links === | ||
* Official Nintendo documentation on TCALL: Table C-16 [https://archive.org/details/SNESDevManual/book1/page/n234 Appendix C-9] | * Official Nintendo documentation on TCALL: Table C-16 [https://archive.org/details/SNESDevManual/book1/page/n234 Appendix C-9] | ||
* [https://www.romhacking.net/documents/197 | * [https://www.romhacking.net/documents/197 anomie's SPC700 doc] | ||
* https://forums.nesdev.org/viewtopic.php?t=13313 | |||
[[Category:ASM]] | [[Category:ASM]] | ||
Latest revision as of 11:40, 20 September 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | Vector Address | |||
| Implied (type 3) | 01 | 1 byte | 8 cycles | $FFDE | |||
| Implied (type 3) | 11 | 1 byte | 8 cycles | $FFDC | |||
| Implied (type 3) | 21 | 1 byte | 8 cycles | $FFDA | |||
| Implied (type 3) | 31 | 1 byte | 8 cycles | $FFD8 | |||
| Implied (type 3) | 41 | 1 byte | 8 cycles | $FFD6 | |||
| Implied (type 3) | 51 | 1 byte | 8 cycles | $FFD4 | |||
| Implied (type 3) | 61 | 1 byte | 8 cycles | $FFD2 | |||
| Implied (type 3) | 71 | 1 byte | 8 cycles | $FFD0 | |||
| Implied (type 3) | 81 | 1 byte | 8 cycles | $FFCE | |||
| Implied (type 3) | 91 | 1 byte | 8 cycles | $FFCC | |||
| Implied (type 3) | A1 | 1 byte | 8 cycles | $FFCA | |||
| Implied (type 3) | B1 | 1 byte | 8 cycles | $FFC8 | |||
| Implied (type 3) | C1 | 1 byte | 8 cycles | $FFC6 | |||
| Implied (type 3) | D1 | 1 byte | 8 cycles | $FFC4 | |||
| Implied (type 3) | E1 | 1 byte | 8 cycles | $FFC2 | |||
| Implied (type 3) | F1 | 1 byte | 8 cycles | $FFC0 | |||
| Flags Affected | |||||||
|---|---|---|---|---|---|---|---|
| N | V | P | B | H | I | Z | C |
| . | . | . | . | . | . | . | . |
TCALL (Table CALl) is an SPC700 instruction that calls a subroutine whose 16-bit address is stored in the uppermost page. The low byte of the address of the vector (pointer to subroutine) is a function of the high nybble of the opcode, equal to $DE - n*2. The high byte of the vector address is always $FF.
No flags are affected.
Syntax
TCALL n
where n is the vector call number, a decimal integer from 0 to 15, which becomes the high nybble of the opcode.
See Also
External Links
- Official Nintendo documentation on TCALL: Table C-16 Appendix C-9
- anomie's SPC700 doc
- https://forums.nesdev.org/viewtopic.php?t=13313