| @ 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 |