Source code in the z80 programming language

ld a,(&C000)  ;load the accumulator with the value from the memory address &C000.

ld hl,&D000
ld e,(hl)     ;load the E register with the byte at memory address &D000.

ld bc,(&E000) ;load the register pair BC from memory address &E000. The Game Boy cannot use this addressing mode.
; This is the same as:
;  ld a,(&E000)
;  ld c,a
;  ld a,(&E001)
;  ld b,a

ld IX,&F000
ld a,(IX+3)   ;load A with the byte stored at &F003, The Game Boy cannot use this addressing mode.

ld h,(bc)    ;if (bc) or (de) is the operand of a LD command, the other operand must be A.
ld e,(&A000) ;if a constant pointer is the operand of a LD command, the other operand must be A.

inc (HL) ;increment the byte pointed to by HL
rrc (IX+5)         ;take the byte pointed to by IX+5 and rotate it right. The value of IX is unchanged.
sub (IY-23)        ;subtract the value of the byte that is 23 bytes before IY, from A. 
                   ;The value of that byte at that address is unchanged, as is IY.

ld hl,PointerTable
ld e,(hl)
inc hl
ld d,(hl)
; depending on what we need to do next, we might need this new pointer back in HL. There are a few ways to do this:
;    ex de,hl

;    push de
;    pop hl

;    ld L,E
;    ld H,D

ld hl,PointerTable
ld a,(hl)
ld (SMC+1),a  ;SMC+1 points to low byte of the operand

inc hl        ;increment HL so we can fetch the high byte

ld a,(hl)
ld (SMC+2),a  ;SMC+2 points to high byte of the operand

SMC:
ld a,&BEEF     ;gets overwritten with the pointer stored in entry 0 of PointerTable.

ld hl,PointerTable
ld a,(index)
add a         ;this is a table of 16-bit values so double our index
add L
ld L,a
ld a,H
adc 0
ld H,a        ;offset HL by our index


ld e,(hl)
inc hl
ld d,(hl)      ;get the Ath entry of PointerTable and store it into DE.

ld (referenceStorage),DE   ;store DE into ram for later use as a reference.