Pokémon mini Development Documentation

Calling routines

Hex	Mnemonic	Cycles,True	or False	Condition
E0 rr	CARS C,rr	5	2	Carry=1
E1 rr	CARS NC,rr	5	2	Carry=0
E2 rr	CARS Z,rr	5	2	Zero=1
E3 rr	CARS NZ,rr	5	2	Zero=0
E8 rr qq	CARL C,qqrr	6	3	Carry=1
E9 rr qq	CARL NC,qqrr	6	3	Carry=0
EA rr qq	CARL Z,qqrr	6	3	Zero=1
EB rr qq	CARL NZ,qqrr	6	3	Zero=0
F0 rr	CARS rr	5	n/a	n/a
F2 rr qq	CARL qqrr	6	n/a	n/a
FB ll hh	CALL [hhll]	5	n/a	n/a
FC kk	INT [kk]	5	n/a	n/a
CE F0 rr	CARS LT,rr	6	3	(Overflow=1) != (Negative=1)
CE F1 rr	CARS LE,rr	6	3	((Overflow=0) != (Negative=0)) OR (Zero=1)
CE F2 rr	CARS GT,rr	6	3	((Overflow=1) == (Negative=1)) AND (Zero=0)
CE F3 rr	CARS GE,rr	6	3	(Overflow=0) == (Negative=0)
CE F4 rr	CARS V,rr	6	3	Overflow=1
CE F5 rr	CARS NV,rr	6	3	Overflow=0
CE F6 rr	CARS P,rr	6	3	Negative=0
CE F7 rr	CARS M,rr	6	3	Negative=1
CE F8 rr	CARS F0,rr	6	3	F0=1*
CE F9 rr	CARS F1,rr	6	3	F1=1 (unused flag)
CE FA rr	CARS F2,rr	6	3	F2=1 (unused flag)
CE FB rr	CARS F3,rr	6	3	F3=1 (unused flag)
CE FC rr	CARS NF0,rr	6	3	F0=0*
CE FD rr	CARS NF1,rr	6	3	F1=0 (unused flag)
CE FE rr	CARS NF2,rr	6	3	F2=0 (unused flag)
CE FF rr	CARS NF3,rr	6	3	F3=0 (unused flag)

* F0 is set on the Pokémon Channel emulator when the previous DIV had a denominator of 0.

Execute

kk     = Lower 8 bits of a vector address
rr     = Immediate signed 8-bits
qqrr   = Immediate signed 16-bits
NB/CB  = Register NB or CB
SP     = Register SP (Stack Pointer)
PC     = Register PC (Program Counter)
[hhll] = Memory: (EP shl 16) or hhll

Conditional CARS

; CARS *,rr

IF (Condition) THEN
  SP = SP - 3
  Memory[SP+2] = CB
  Memory[SP+1] = PC SRL 8
  Memory[SP]   = PC AND 0x00FF
  CB = NB
  PC = PC + rr - 1
ENDIF

Conditional CARL

; CARL *,qqrr

IF (Condition) THEN
  SP = SP - 3
  Memory[SP+2] = CB
  Memory[SP+1] = PC SRL 8
  Memory[SP]   = PC AND 0x00FF
  CB = NB
  PC = PC + qqrr - 1
ENDIF

CARS

; CARS rr

SP = SP - 3
Memory[SP+2] = CB
Memory[SP+1] = PC SRL 8
Memory[SP]   = PC AND 0x00FF
CB = NB
PC = PC + rr - 1

CARL

; CARL qqrr

SP = SP - 3
Memory[SP+2] = CB
Memory[SP+1] = PC SRL 8
Memory[SP]   = PC AND 0x00FF
CB = NB
PC = PC + qqrr - 1

CALL

; CALL [hhll]

SP = SP - 3
Memory[SP+2] = CB
Memory[SP+1] = PC SRL 8
Memory[SP]   = PC AND 0x00FF
CB = NB
PC = Memory16[(EP SLL 16) + hhll]

INT

; INT [kk]  ;; (not fully tested)

SP = SP - 4
Memory[SP+3] = CB
Memory[SP+2] = PC SRL 8
Memory[SP+1] = PC AND 0x00FF
Memory[SP]   = SC
CB = NB
PC = Memory16[kk]

Description

Call a subroutine (CARS/CARL/CALL) or a interrupt vector (INT).

Use RET to return from a subroutine and RETE from a interrupt.

NOTE: All non-branch instructions do “NB = CB” causing NB to be restored, any branch that requires banking needs “LD NB, A” or “LD NB, #nn” directly before any call.

Conditions

None

Examples

; A = 0x10
; B = 0x10
CALL somefunction
; A = 0x11
; B = 0x0F
BIT B, #0x10
; SC = (Zero=0):(Negative=0)
CARS Z,somefunction    ; Condition fails, call not taken
; A = 0x11
; B = 0x0F
; SC = (Zero=0):(Negative=0)
CARS NS,somefunction   ; Condition succeeds
; A = 0x12
; B = 0x0E

 (...)

somefunction:
  INC A
  DEC B
  RET                   ; Return from the call

; Calling a subroutine in different bank
LD NB, $0F
CALL function_at_bank_16

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