Rearrange MpegEncContext to simplify access from asm

This moves the fields needed by asm near the top, before any
structs or other members which complicate the offset calculation.
Modifying other structs will no longer require updating the offsets,
and the asm code is slightly simpler due to the smaller offsets.

Signed-off-by: Mans Rullgard <mans@mansr.com>

libavcodec/arm/asm-offsets.h

@@ -29,20 +29,11 @@
 #endif
 
 /* MpegEncContext */
-#if defined(__ARM_EABI__) || defined(__eabi__)
-#define Y_DC_SCALE               0xab4
-#define C_DC_SCALE               0xab8
-#define AC_PRED                  0xae0
-#define BLOCK_LAST_INDEX         0x21c0
-#define INTER_SCANTAB_RASTER_END 0x23c0
-#define H263_AIC                 0x2670
-#elif defined(__APPLE__)
-#define Y_DC_SCALE               0xa70
-#define C_DC_SCALE               0xa74
-#define AC_PRED                  0xa9c
-#define BLOCK_LAST_INDEX         0x217c
-#define INTER_SCANTAB_RASTER_END 0x237c
-#define H263_AIC                 0x2620
-#endif
+#define Y_DC_SCALE               0xb4
+#define C_DC_SCALE               0xb8
+#define AC_PRED                  0xbc
+#define BLOCK_LAST_INDEX         0xc0
+#define H263_AIC                 0xf0
+#define INTER_SCANTAB_RASTER_END 0x138
 
 #endif

libavcodec/arm/mpegvideo_neon.S

@@ -22,10 +22,9 @@
 #include "asm-offsets.h"
 
 function ff_dct_unquantize_h263_inter_neon, export=1
-        add             r0,  r0,  #0x2200
-        add             r12, r0,  #BLOCK_LAST_INDEX-0x2200
+        add             r12, r0,  #BLOCK_LAST_INDEX
         ldr             r12, [r12, r2, lsl #2]
-        add             r0,  r0,  #INTER_SCANTAB_RASTER_END-0x2200
+        add             r0,  r0,  #INTER_SCANTAB_RASTER_END
         ldrb            r12, [r0, r12]
         sub             r2,  r3,  #1
         lsl             r0,  r3,  #1
@@ -75,17 +74,15 @@ endfunc
 
 function ff_dct_unquantize_h263_intra_neon, export=1
         push            {r4-r6,lr}
+        add             r12, r0,  #BLOCK_LAST_INDEX
         ldr             r6,  [r0, #AC_PRED]
-        add             r5,  r0,  #0x2700
+        add             lr,  r0,  #INTER_SCANTAB_RASTER_END
         cmp             r6,  #0
         movne           r12, #63
         bne             1f
-        add             lr,  r0,  #0x2200
-        add             r12, lr,  #BLOCK_LAST_INDEX-0x2200
-        add             lr,  lr,  #INTER_SCANTAB_RASTER_END-0x2200
         ldr             r12, [r12, r2, lsl #2]
         ldrb            r12, [lr, r12]
-1:      ldr             r5,  [r5, #H263_AIC-0x2700]
+1:      ldr             r5,  [r0, #H263_AIC]
         ldrsh           r4,  [r1]
         cmp             r5,  #0
         mov             r5,  r1

libavcodec/mpegvideo.h

@@ -224,9 +224,6 @@ typedef struct MpegEncContext {
     int stream_codec_tag;      ///< internal stream_codec_tag upper case converted from avctx stream_codec_tag
     /* the following fields are managed internally by the encoder */
 
-    /** bit output */
-    PutBitContext pb;
-
     /* sequence parameters */
     int context_initialized;
     int input_picture_number;  ///< used to set pic->display_picture_number, should not be used for/by anything else
@@ -247,6 +244,23 @@ typedef struct MpegEncContext {
     Picture **input_picture;   ///< next pictures on display order for encoding
     Picture **reordered_input_picture; ///< pointer to the next pictures in codedorder for encoding
 
+    int y_dc_scale, c_dc_scale;
+    int ac_pred;
+    int block_last_index[12];  ///< last non zero coefficient in block
+    int h263_aic;              ///< Advanded INTRA Coding (AIC)
+
+    /* scantables */
+    ScanTable inter_scantable; ///< if inter == intra then intra should be used to reduce tha cache usage
+    ScanTable intra_scantable;
+    ScanTable intra_h_scantable;
+    ScanTable intra_v_scantable;
+
+    /* WARNING: changes above this line require updates to hardcoded
+     *          offsets used in asm. */
+
+    /** bit output */
+    PutBitContext pb;
+
     int start_mb_y;            ///< start mb_y of this thread (so current thread should process start_mb_y <= row < end_mb_y)
     int end_mb_y;              ///< end   mb_y of this thread (so current thread should process start_mb_y <= row < end_mb_y)
     struct MpegEncContext *thread_context[MAX_THREADS];
@@ -283,7 +297,6 @@ typedef struct MpegEncContext {
     int16_t *dc_val_base;
     int16_t *dc_val[3];            ///< used for mpeg4 DC prediction, all 3 arrays must be continuous
     int16_t dc_cache[4*5];
-    int y_dc_scale, c_dc_scale;
     const uint8_t *y_dc_scale_table;     ///< qscale -> y_dc_scale table
     const uint8_t *c_dc_scale_table;     ///< qscale -> c_dc_scale table
     const uint8_t *chroma_qscale_table;  ///< qscale -> chroma_qscale (h263)
@@ -291,7 +304,6 @@ typedef struct MpegEncContext {
     uint8_t *coded_block;          ///< used for coded block pattern prediction (msmpeg4v3, wmv1)
     int16_t (*ac_val_base)[16];
     int16_t (*ac_val[3])[16];      ///< used for for mpeg4 AC prediction, all 3 arrays must be continuous
-    int ac_pred;
     uint8_t *prev_pict_types;     ///< previous picture types in bitstream order, used for mb skip
 #define PREV_PICT_TYPES_BUFFER_SIZE 256
     int mb_skipped;                ///< MUST BE SET only during DECODING
@@ -434,12 +446,6 @@ typedef struct MpegEncContext {
     /** identical to the above but for MMX & these are not permutated, second 64 entries are bias*/
     uint16_t (*q_intra_matrix16)[2][64];
     uint16_t (*q_inter_matrix16)[2][64];
-    int block_last_index[12];  ///< last non zero coefficient in block
-    /* scantables */
-    ScanTable intra_scantable;
-    ScanTable intra_h_scantable;
-    ScanTable intra_v_scantable;
-    ScanTable inter_scantable; ///< if inter == intra then intra should be used to reduce tha cache usage
 
     /* noise reduction */
     int (*dct_error_sum)[64];
@@ -495,7 +501,6 @@ typedef struct MpegEncContext {
 
     /* H.263+ specific */
     int umvplus;                    ///< == H263+ && unrestricted_mv
-    int h263_aic;                   ///< Advanded INTRA Coding (AIC)
     int h263_aic_dir;               ///< AIC direction: 0 = left, 1 = top
     int h263_slice_structured;
     int alt_inter_vlc;              ///< alternative inter vlc