Direct Page Addressing: Difference between revisions

Revision as of 21:48, 2 August 2024

Direct Page Addressing is an addressing mode that is supported by the 65c816 and SPC700. It is an upgraded version of zero page addressing. The effective addresses generated by it are always in bank 0.^[4]

The operand specifies which byte of the direct page to access.

Syntax

LDA dp

Supported by 24 instructions on the '816:

ADC (opcode 65)
SBC (opcode E5)
EOR (opcode 45)
ASL (opcode 06)
LSR (opcode 46)
INC (opcode E6)
DEC (opcode C6)
BIT (opcode 24)
CMP (opcode C5)
CPX (opcode E4)
CPY (opcode C4)
ORA (opcode 05)
AND (opcode 25)
LDA (opcode A5)
LDX (opcode A6)
LDY (opcode A4)
ROL (opcode 26)
ROR (opcode 66)
STA (opcode 85)
STX (opcode 86)
STY (opcode 84)
STZ (opcode 64)
TRB (opcode 14)
TSB (opcode 04)

References

Eyes & Lichty, page 389: https://archive.org/details/0893037893ProgrammingThe65816/page/389
lbid, page 114: https://archive.org/details/0893037893ProgrammingThe65816/page/114
section 3.5.17 of 65c816 datasheet, https://westerndesigncenter.com/wdc/documentation/w65c816s.pdf
lbid, section 3.3

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-'''Direct Page Addressing''' is an [[addressing mode]] that is supported by the [[65c816]] and [[SPC700]].  The effective addresses generated by it are always in [[bank]] 0.<sup>[4]</sup>
+'''Direct Page Addressing''' is an [[addressing mode]] that is supported by the [[65c816]] and [[SPC700]].  It is an upgraded version of [[zero page addressing]].  The effective addresses generated by it are always in [[bank]] 0.<sup>[4]</sup>
 The operand specifies which byte of the [[direct page]] to access.
@@ Line 35: / Line 35: @@
 === See Also ===
-* [[Zero Page Addressing]]
 * [[Direct Page Indexed, X Addressing]]
 * [[Direct Page Indexed, Y Addressing]]