; General macros

; Reads A from addr, from $FF00 to $FFFF
; Preserved: F, BC, DE, HL
; Time: 3 cycles
.macro lda ARGS addr
     ldh  a,(addr - $FF00)
.endm

; Writes A to addr, from $FF00 to $FFFF
; Preserved: AF, BC, DE, HL
; Time: 3 cycles
.macro sta ARGS addr
     ldh  (addr - $FF00),a
.endm

; Writes immediate data to addr, from $FF00 to $FFFF
; Preserved: F, BC, DE, HL
; Time: 5 cycles
.macro wreg ARGS addr, data
     ld   a,data
     sta  addr
.endm

; Calls routine multiple times, with A having the
; value 'start' the first time, 'start+step' the
; second time, up to 'end' for the last time.
; Preserved: BC, DE, HL
.macro for_loop ; routine,start,end,step
     ld   a,\2
     
for_loop\@:
     push af
     call \1
     pop  af
     
     add  \4
     cp   <(\3 + \4)
     jr   nz,for_loop\@
.endm

; Calls routine n times. The value of A in the routine
; counts from 0 to n-1.
; Preserved: BC, DE, HL
.macro loop_n_times ; routine,n
     for_loop \1,0,\2 - 1,+1
.endm

; Same as for_loop, but counts with 16-bit value in BC.
; Preserved: DE, HL
.macro for_loop16 ; routine,start,end,step
     ld   bc,\2
     
for_loop16\@:
     push bc
     call \1
     pop  bc
     
     ld   a,c
     add  <\4
     ld   c,a
     
     ld   a,b
     adc  >\4
     ld   b,a
     
     cp   >(\3+\4)
     jr   nz,for_loop16\@
     
     ld   a,c
     cp   <(\3+\4)
     jr   nz,for_loop16\@
.endm