1 files changed, 36 insertions, 0 deletions
diff --git a/floor1ARM.s b/floor1ARM.s
new file mode 100644
index 0000000..689b5c5
--- /dev/null
+++ b/floor1ARM.s
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+; Tremolo library
+; Copyright (C) 2009 Robin Watts for Pinknoise Productions Ltd
+
+	AREA	|.text|, CODE, READONLY
+
+	EXPORT	render_line_arm
+
+render_line_arm
+	; 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