Pokémon mini Development Documentation

ADD = Addition (8-bits)

Hex	Mnemonic	Cycles
00	ADD A,A	2
01	ADD A,B	2
02 nn	ADD A,#nn	2
03	ADD A,[HL]	2
04 ll	ADD A,[BR:ll]	3
05 ll hh	ADD A,[hhll]	4
06	ADD A,[IX]	2
07	ADD A,[IY]	2
CE 00 dd	ADD A,[IX+dd]	4
CE 01 dd	ADD A,[IY+dd]	4
CE 02	ADD A,[IX+L]	4
CE 03	ADD A,[IY+L]	4
CE 04	ADD [HL],A	4
CE 05 nn	ADD [HL],#nn	5
CE 06	ADD [HL],[IX]	5
CE 07	ADD [HL],[IY]	5

Execute

#nn     = Immediate unsigned 8-bits
dd      = Immediate signed 8-bits
A       = Register A
B       = Register B
[BR:ll] = Memory: (EP shl 16) or (BR shl 8) or #nn
[HL]    = Memory: (EP shl 16) or HL
[IX]     = Memory: (XP shl 16) or IX
[IY]     = Memory: (YP shl 16) or IY
[hhll]  = Memory: (EP shl 16) or hhll
[IX+dd] = Memory: (XP shl 16) or (IX + dd)
[IY+dd] = Memory: (YP shl 16) or (IY + dd)
[IX+L]  = Memory: (XP shl 16) or (IX + signed(L))
[IY+L]  = Memory: (YP shl 16) or (IY + signed(L))

; ADD Ds, Sc
;
; Ds = Destination
; Sc = Source

; (If flags D=0 and U=0)
Ds = Ds + Sc

;------------------------------------------------

; (If flags D=0 and U=1)
Ds & 0x0F = (Ds & 0x0F) + (Sc & 0x0F)

;------------------------------------------------

; (If flags D=1 and U=0)
IF (((Ds & 15) + (Sc & 15)) >= 10) THEN
  Ds = Ds + Sc + 6
ELSE
  Ds = Ds + Sc
ENDIF
IF (Ds >= 0xA0) Ds = Ds + 0x60

;------------------------------------------------

; (If flags D=1 and U=1)
IF (((Ds & 15) + (Sc & 15)) >= 10) THEN
  Ds & 0x0F = (Ds & 0x0F) + (Sc & 0x0F) + 6
ELSE
  Ds & 0x0F = (Ds & 0x0F) + (Sc & 0x0F)
ENDIF

Description

8-bits Source adds to the 8-bits Destination.

Conditions

If flags D=0 and U=0

Zero: Set when result is 0
Carry: Set when result is >= 256
Overflow: Set when result exceeds 8-bits signed range (< -128 OR >127)
Negative: Set when bit 7 of the result is 1

If flags D=0 and U=1

Zero: Set when result is 0
Carry: Set when result is >= 16
Overflow: Set when result exceeds 4-bits signed range (< -16 OR > 15)
Negative: Set when bit 3 of the result is 1

If flags D=1 and U=0

Zero: Set when result is 0
Carry: Set when result is >= 100
Overflow: Always reset
Negative: Always reset

If flags D=1 and U=1

Zero: Set when result is 0
Carry: Set when result is >= 10
Overflow: Always reset
Negative: Always reset

Examples

; A = 0x55
ADD A, $80
; A = 0xD5 (0x55 + 0x80 = 0x(0)D5)
; SC = (Zero=0):(Carry=0):(Overflow=1):(Negative=1)

; B = 0x31
; A = 0xCF
ADD A, B
; B = 0x31
; A = 0x00 (0xCF + 0x31 = 0x(1)00)
; SC = (Zero=1):(Carry=1):(Overflow=0):(Negative=0)

; [HL] = 0xDE
; A = 0xCF
ADD A, [HL]
; [HL] = 0xDE
; A = 0xAD (0xCF + 0xDE = 0x(1)AD)
; SC = (Zero=0):(Carry=1):(Overflow=0):(Negative=1)

; ( Decimal = 1, Unpack = 0 )
; A = 0x09
ADD A,``
``$01
; A = 0x10 (09 + 01 = 10)
; SC = (Zero=0):(Carry=0):(Overflow=0):(Negative=0)

; ( Decimal = 0, Unpack = 1 )
; A = 0x3F (Note, in "unpack mode" the high nibble is always discarded)
ADD A, $01
; A = 0x00 (0xF + 0x1 = 0x(1)0)
; SC = (Zero=1):(Carry=1):(Overflow=0):(Negative=0)

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