diff options
Diffstat (limited to 'Tremolo/bitwiseARM.s')
| -rw-r--r-- | Tremolo/bitwiseARM.s | 368 |
1 files changed, 368 insertions, 0 deletions
diff --git a/Tremolo/bitwiseARM.s b/Tremolo/bitwiseARM.s new file mode 100644 index 0000000..f79b26e --- /dev/null +++ b/Tremolo/bitwiseARM.s @@ -0,0 +1,368 @@ +@ Tremolo library +@ Copyright (C) 2009 Robin Watts for Pinknoise Productions Ltd + + .text + + .global oggpack_look + .global oggpack_adv + .global oggpack_readinit + .global oggpack_read + +oggpack_look: + @ r0 = oggpack_buffer *b + @ r1 = int bits + STMFD r13!,{r10,r11,r14} + LDMIA r0,{r2,r3,r12} + @ r2 = bitsLeftInSegment + @ r3 = ptr + @ r12= bitsLeftInWord + SUBS r2,r2,r1 @ bitsLeftinSegment -= bits + BLT look_slow @ Not enough bits in this segment for + @ this request. Do it slowly. + LDR r10,[r3] @ r10= ptr[0] + RSB r14,r12,#32 @ r14= 32-bitsLeftInWord + SUBS r12,r12,r1 @ r12= bitsLeftInWord -= bits + LDRLT r11,[r3,#4]! @ r11= ptr[1] + MOV r10,r10,LSR r14 @ r10= ptr[0]>>(32-bitsLeftInWord) + ADDLE r12,r12,#32 @ r12= bitsLeftInWord += 32 + RSB r14,r14,#32 @ r14= 32-bitsLeftInWord + ORRLT r10,r10,r11,LSL r14 @ r10= Next 32 bits. + MOV r14,#1 + RSB r14,r14,r14,LSL r1 + AND r0,r10,r14 + LDMFD r13!,{r10,r11,PC} + +look_slow: + STMFD r13!,{r5,r6} + ADDS r10,r2,r1 @ r10= bitsLeftInSegment + bits (i.e. + @ the initial value of bitsLeftInSeg) + @ r10 = bitsLeftInSegment (initial) + @ r12 = bitsLeftInWord + RSB r14,r12,#32 @ r14= 32-bitsLeftInWord + MOV r5,r10 @ r5 = bitsLeftInSegment (initial) + BLT look_overrun + BEQ look_next_segment @ r10= r12 = 0, if we branch + CMP r12,r10 @ If bitsLeftInWord < bitsLeftInSeg + @ there must be more in the next word + LDR r10,[r3],#4 @ r10= ptr[0] + LDRLT r6,[r3] @ r6 = ptr[1] + MOV r11,#1 + MOV r10,r10,LSR r14 @ r10= first bitsLeftInWord bits + ORRLT r10,r10,r6,LSL r12 @ r10= first bitsLeftInSeg bits+crap + RSB r11,r11,r11,LSL r5 @ r11= mask + AND r10,r10,r11 @ r10= first r5 bits + @ Load the next segments data +look_next_segment: + @ At this point, r10 contains the first r5 bits of the result + LDR r11,[r0,#12] @ r11= head = b->head + @ Stall + @ Stall +look_next_segment_2: + LDR r11,[r11,#12] @ r11= head = head->next + @ Stall + @ Stall + CMP r11,#0 + BEQ look_out_of_data + LDMIA r11,{r6,r12,r14} @ r6 = buffer + @ r12= begin + @ r14= length + LDR r6,[r6] @ r6 = buffer->data + CMP r14,#0 + BEQ look_next_segment_2 + ADD r6,r6,r12 @ r6 = buffer->data+begin +look_slow_loop: + LDRB r12,[r6],#1 @ r12= *buffer + SUBS r14,r14,#1 @ r14= length + @ Stall + ORR r10,r10,r12,LSL r5 @ r10= first r5+8 bits + ADD r5,r5,#8 + BLE look_really_slow + CMP r5,r1 + BLT look_slow_loop + MOV r14,#1 + RSB r14,r14,r14,LSL r1 + AND r0,r10,r14 + LDMFD r13!,{r5,r6,r10,r11,PC} + + +look_really_slow: + CMP r5,r1 + BLT look_next_segment_2 + MOV r14,#1 + RSB r14,r14,r14,LSL r1 + AND r0,r10,r14 + LDMFD r13!,{r5,r6,r10,r11,PC} + +look_out_of_data: + @MVN r0,#0 ; return -1 + MOV r0,#0 + LDMFD r13!,{r5,r6,r10,r11,PC} + +look_overrun: + @ We had overrun when we started, so we need to skip -r10 bits. + LDR r11,[r0,#12] @ r11 = head = b->head + @ stall + @ stall +look_overrun_next_segment: + LDR r11,[r11,#12] @ r11 = head->next + @ stall + @ stall + CMP r11,#0 + BEQ look_out_of_data + LDMIA r11,{r6,r7,r14} @ r6 = buffer + @ r7 = begin + @ r14= length + LDR r6,[r6] @ r6 = buffer->data + @ stall + @ stall + ADD r6,r6,r7 @ r6 = buffer->data+begin + MOV r14,r14,LSL #3 @ r14= length in bits + ADDS r14,r14,r10 @ r14= length in bits-bits to skip + MOVLE r10,r14 + BLE look_overrun_next_segment + RSB r10,r10,#0 @ r10= bits to skip + ADD r6,r10,r10,LSR #3 @ r6 = pointer to data + MOV r10,#0 + B look_slow_loop + +oggpack_adv: + @ r0 = oggpack_buffer *b + @ r1 = bits + LDMIA r0,{r2,r3,r12} + @ r2 = bitsLeftInSegment + @ r3 = ptr + @ r12= bitsLeftInWord + SUBS r2,r2,r1 @ Does this run us out of bits in the + BLE adv_slow @ segment? If so, do it slowly + SUBS r12,r12,r1 + ADDLE r12,r12,#32 + ADDLE r3,r3,#4 + STMIA r0,{r2,r3,r12} + MOV PC,R14 +adv_slow: + STMFD r13!,{r10,r14} + + LDR r14,[r0,#12] @ r14= head + @ stall +adv_slow_loop: + LDR r1,[r0,#20] @ r1 = count + LDR r10,[r14,#8] @ r10= head->length + LDR r14,[r14,#12] @ r14= head->next + @ stall + ADD r1,r1,r10 @ r1 = count += head->length + CMP r14,#0 + BEQ adv_end + STR r1,[r0,#20] @ b->count = count + STR r14,[r0,#12] @ b->head = head + LDMIA r14,{r3,r10,r12} @ r3 = buffer + @ r10= begin + @ r12= length + LDR r3,[r3] @ r3 = buffer->data + ADD r3,r3,r10 @ r3 = Pointer to start (byte) + AND r10,r3,#3 @ r10= bytes to backtrk to word align + MOV r10,r10,LSL #3 @ r10= bits to backtrk to word align + RSB r10,r10,#32 @ r10= bits left in word + ADDS r10,r10,r2 @ r10= bits left in word after skip + ADDLE r10,r10,#32 + ADDLE r3,r3,#4 + BIC r3,r3,#3 @ r3 = Pointer to start (word) + ADDS r2,r2,r12,LSL #3 @ r2 = length in bits after advance + BLE adv_slow_loop + STMIA r0,{r2,r3,r10} + + LDMFD r13!,{r10,PC} +adv_end: + MOV r2, #0 + MOV r12,#0 + STMIA r0,{r2,r3,r12} + + LDMFD r13!,{r10,PC} + +oggpack_readinit: + @ r0 = oggpack_buffer *b + @ r1 = oggreference *r + STR r1,[r0,#12] @ b->head = r1 + STR r1,[r0,#16] @ b->tail = r1 + LDMIA r1,{r2,r3,r12} @ r2 = b->head->buffer + @ r3 = b->head->begin + @ r12= b->head->length + LDR r2,[r2] @ r2 = b->head->buffer->data + MOV r1,r12,LSL #3 @ r1 = BitsInSegment + MOV r12,#0 + ADD r3,r2,r3 @ r3 = r2+b->head->begin + BIC r2,r3,#3 @ r2 = b->headptr (word) + AND r3,r3,#3 + MOV r3,r3,LSL #3 + RSB r3,r3,#32 @ r3 = BitsInWord + STMIA r0,{r1,r2,r3} + STR r12,[r0,#20] + MOV PC,R14 + +oggpack_read: + @ r0 = oggpack_buffer *b + @ r1 = int bits + STMFD r13!,{r10,r11,r14} + LDMIA r0,{r2,r3,r12} + @ r2 = bitsLeftInSegment + @ r3 = ptr + @ r12= bitsLeftInWord + SUBS r2,r2,r1 @ bitsLeftinSegment -= bits + BLT read_slow @ Not enough bits in this segment for + @ this request. Do it slowly. + LDR r10,[r3] @ r10= ptr[0] + RSB r14,r12,#32 @ r14= 32-bitsLeftInWord + SUBS r12,r12,r1 @ r12= bitsLeftInWord -= bits + ADDLE r3,r3,#4 + LDRLT r11,[r3] @ r11= ptr[1] + MOV r10,r10,LSR r14 @ r10= ptr[0]>>(32-bitsLeftInWord) + ADDLE r12,r12,#32 @ r12= bitsLeftInWord += 32 + RSB r14,r14,#32 @ r14= 32-bitsLeftInWord + ORRLT r10,r10,r11,LSL r14 @ r10= Next 32 bits. + STMIA r0,{r2,r3,r12} + MOV r14,#1 + RSB r14,r14,r14,LSL r1 + AND r0,r10,r14 + LDMFD r13!,{r10,r11,PC} + +read_slow: + STMFD r13!,{r5,r6} + ADDS r10,r2,r1 @ r10= bitsLeftInSegment + bits (i.e. + @ the initial value of bitsLeftInSeg) + @ r10 = bitsLeftInSegment (initial) + @ r12 = bitsLeftInWord + RSB r14,r12,#32 @ r14= 32-bitsLeftInWord + MOV r5,r10 @ r5 = bitsLeftInSegment (initial) + BLT read_overrun + BEQ read_next_segment @ r10= r12 = 0, if we branch + CMP r12,r10 @ If bitsLeftInWord < bitsLeftInSeg + @ there must be more in the next word + LDR r10,[r3],#4 @ r10= ptr[0] + LDRLT r6,[r3] @ r6 = ptr[1] + MOV r11,#1 + MOV r10,r10,LSR r14 @ r10= first bitsLeftInWord bits + ORRLT r10,r10,r6,LSL r12 @ r10= first bitsLeftInSeg bits+crap + RSB r11,r11,r11,LSL r5 @ r11= mask + AND r10,r10,r11 @ r10= first r5 bits + @ Load the next segments data +read_next_segment: + @ At this point, r10 contains the first r5 bits of the result + LDR r11,[r0,#12] @ r11= head = b->head + @ Stall +read_next_segment_2: + @ r11 = head + LDR r6,[r0,#20] @ r6 = count + LDR r12,[r11,#8] @ r12= length + LDR r11,[r11,#12] @ r11= head = head->next + @ Stall + ADD r6,r6,r12 @ count += length + CMP r11,#0 + BEQ read_out_of_data + STR r11,[r0,#12] + STR r6,[r0,#20] @ b->count = count + LDMIA r11,{r6,r12,r14} @ r6 = buffer + @ r12= begin + @ r14= length + LDR r6,[r6] @ r6 = buffer->data + CMP r14,#0 + BEQ read_next_segment_2 + ADD r6,r6,r12 @ r6 = buffer->data+begin +read_slow_loop: + LDRB r12,[r6],#1 @ r12= *buffer + SUBS r14,r14,#1 @ r14= length + @ Stall + ORR r10,r10,r12,LSL r5 @ r10= first r5+8 bits + ADD r5,r5,#8 + BLE read_really_slow + CMP r5,r1 + BLT read_slow_loop +read_end: + MOV r12,#1 + RSB r12,r12,r12,LSL r1 + + @ Store back the new position + @ r2 = -number of bits to go from this segment + @ r6 = ptr + @ r14= bytesLeftInSegment + @ r11= New head value + LDMIA r11,{r3,r6,r14} @ r3 = buffer + @ r6 = begin + @ r14= length + LDR r3,[r3] @ r3 = buffer->data + ADD r1,r2,r14,LSL #3 @ r1 = bitsLeftInSegment + @ stall + ADD r6,r3,r6 @ r6 = pointer + AND r3,r6,#3 @ r3 = bytes used in first word + RSB r3,r2,r3,LSL #3 @ r3 = bits used in first word + BIC r2,r6,#3 @ r2 = word ptr + RSBS r3,r3,#32 @ r3 = bitsLeftInWord + ADDLE r3,r3,#32 + ADDLE r2,r2,#4 + STMIA r0,{r1,r2,r3} + + AND r0,r10,r12 + LDMFD r13!,{r5,r6,r10,r11,PC} + + +read_really_slow: + CMP r5,r1 + BGE read_end + LDR r14,[r11,#8] @ r14= length of segment just done + @ stall + @ stall + ADD r2,r2,r14,LSL #3 @ r2 = -bits to use from next seg + B read_next_segment_2 + +read_out_of_data: + @ Store back the new position + @ r2 = -number of bits to go from this segment + @ r6 = ptr + @ r14= bytesLeftInSegment + @ RJW: This may be overkill - we leave the buffer empty, with -1 + @ bits left in it. We might get away with just storing the + @ bitsLeftInSegment as -1. + LDR r11,[r0,#12] @ r11=head + + LDMIA r11,{r3,r6,r14} @ r3 = buffer + @ r6 = begin + @ r14= length + LDR r3,[r3] @ r3 = buffer->data + ADD r6,r3,r6 @ r6 = pointer + ADD r6,r6,r14 + AND r3,r6,#3 @ r3 = bytes used in first word + MOV r3,r3,LSL #3 @ r3 = bits used in first word + BIC r2,r6,#3 @ r2 = word ptr + RSBS r3,r3,#32 @ r3 = bitsLeftInWord + MVN r1,#0 @ r1 = -1 = bitsLeftInSegment + STMIA r0,{r1,r2,r3} + @MVN r0,#0 ; return -1 + MOV r0,#0 + LDMFD r13!,{r5,r6,r10,r11,PC} + +read_overrun: + @ We had overrun when we started, so we need to skip -r10 bits. + LDR r11,[r0,#12] @ r11 = head = b->head + @ stall + @ stall +read_overrun_next_segment: + LDR r11,[r11,#12] @ r11 = head->next + @ stall + @ stall + CMP r11,#0 + BEQ read_out_of_data + LDMIA r11,{r6,r7,r14} @ r6 = buffer + @ r7 = begin + @ r14= length + LDR r6,[r6] @ r6 = buffer->data + @ stall + @ stall + ADD r6,r6,r7 @ r6 = buffer->data+begin + MOV r14,r14,LSL #3 @ r14= length in bits + ADDS r14,r14,r10 @ r14= length in bits-bits to skip + MOVLE r10,r14 + BLE read_overrun_next_segment + RSB r10,r10,#0 @ r10= bits to skip + ADD r6,r10,r10,LSR #3 @ r6 = pointer to data + MOV r10,#0 + B read_slow_loop + + @ END |