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@ Tremolo library
@ Copyright (C) 2009 Robin Watts for Pinknoise Productions Ltd
.text
.global render_lineARM
render_lineARM:
@ r0 = n
@ r1 = d
@ r2 = floor
@ r3 = base
@ <> = err
@ <> = adx
@ <> = ady
MOV r12,r13
STMFD r13!,{r4-r6,r11,r14}
LDMFD r12,{r11,r12,r14} @ r11 = err
@ r12 = adx
@ r14 = ady
rl_loop:
LDR r4,[r1] @ r4 = *d
LDR r5,[r2],r3,LSL #2 @ r5 = *floor r2 = floor+base
SUBS r11,r11,r14 @ err -= ady
ADDLT r11,r11,r12 @ if (err < 0) err+=adx
SMULL r6, r5, r4, r5 @ (r6,r5) = *d * *floor
ADDLT r2, r2, #4 @ floor+=1
MOVS r6, r6, LSR #15
ADC r5, r6, r5, LSL #17 @ r5 = MULT31_SHIFT15
STR r5,[r1],#4
SUBS r0, r0, #1
BGT rl_loop
LDMFD r13!,{r4-r6,r11,PC}
@ END
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