| @@ -1,14 +1,14 @@ | | | @@ -1,14 +1,14 @@ |
| 1 | /* $NetBSD: ring.h,v 1.11 2008/08/22 15:28:11 cegger Exp $ */ | | 1 | /* $NetBSD: ring.h,v 1.12 2011/07/27 23:10:40 matt Exp $ */ |
| 2 | /****************************************************************************** | | 2 | /****************************************************************************** |
| 3 | * ring.h | | 3 | * ring.h |
| 4 | * | | 4 | * |
| 5 | * Shared producer-consumer ring macros. | | 5 | * Shared producer-consumer ring macros. |
| 6 | * | | 6 | * |
| 7 | * Permission is hereby granted, free of charge, to any person obtaining a copy | | 7 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 8 | * of this software and associated documentation files (the "Software"), to | | 8 | * of this software and associated documentation files (the "Software"), to |
| 9 | * deal in the Software without restriction, including without limitation the | | 9 | * deal in the Software without restriction, including without limitation the |
| 10 | * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or | | 10 | * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| 11 | * sell copies of the Software, and to permit persons to whom the Software is | | 11 | * sell copies of the Software, and to permit persons to whom the Software is |
| 12 | * furnished to do so, subject to the following conditions: | | 12 | * furnished to do so, subject to the following conditions: |
| 13 | * | | 13 | * |
| 14 | * The above copyright notice and this permission notice shall be included in | | 14 | * The above copyright notice and this permission notice shall be included in |
| @@ -50,27 +50,27 @@ typedef unsigned int RING_IDX; | | | @@ -50,27 +50,27 @@ typedef unsigned int RING_IDX; |
| 50 | #define __RD2(_x) (((_x) & 0x00000002) ? 0x2 : ((_x) & 0x1)) | | 50 | #define __RD2(_x) (((_x) & 0x00000002) ? 0x2 : ((_x) & 0x1)) |
| 51 | #define __RD4(_x) (((_x) & 0x0000000c) ? __RD2((_x)>>2)<<2 : __RD2(_x)) | | 51 | #define __RD4(_x) (((_x) & 0x0000000c) ? __RD2((_x)>>2)<<2 : __RD2(_x)) |
| 52 | #define __RD8(_x) (((_x) & 0x000000f0) ? __RD4((_x)>>4)<<4 : __RD4(_x)) | | 52 | #define __RD8(_x) (((_x) & 0x000000f0) ? __RD4((_x)>>4)<<4 : __RD4(_x)) |
| 53 | #define __RD16(_x) (((_x) & 0x0000ff00) ? __RD8((_x)>>8)<<8 : __RD8(_x)) | | 53 | #define __RD16(_x) (((_x) & 0x0000ff00) ? __RD8((_x)>>8)<<8 : __RD8(_x)) |
| 54 | #define __RD32(_x) (((_x) & 0xffff0000) ? __RD16((_x)>>16)<<16 : __RD16(_x)) | | 54 | #define __RD32(_x) (((_x) & 0xffff0000) ? __RD16((_x)>>16)<<16 : __RD16(_x)) |
| 55 | | | 55 | |
| 56 | /* | | 56 | /* |
| 57 | * Calculate size of a shared ring, given the total available space for the | | 57 | * Calculate size of a shared ring, given the total available space for the |
| 58 | * ring and indexes (_sz), and the name tag of the request/response structure. | | 58 | * ring and indexes (_sz), and the name tag of the request/response structure. |
| 59 | * A ring contains as many entries as will fit, rounded down to the nearest | | 59 | * A ring contains as many entries as will fit, rounded down to the nearest |
| 60 | * power of two (so we can mask with (size-1) to loop around). | | 60 | * power of two (so we can mask with (size-1) to loop around). |
| 61 | */ | | 61 | */ |
| 62 | #define __RING_SIZE(_s, _sz) \ | | 62 | #define __RING_SIZE(_s, _sz) \ |
| 63 | (__RD32(((_sz) - (long)(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0]))) | | 63 | (__RD32(((_sz) - offsetof(__typeof__(*(_s)), ring)) / sizeof((_s)->ring[0]))) |
| 64 | | | 64 | |
| 65 | /* | | 65 | /* |
| 66 | * Macros to make the correct C datatypes for a new kind of ring. | | 66 | * Macros to make the correct C datatypes for a new kind of ring. |
| 67 | * | | 67 | * |
| 68 | * To make a new ring datatype, you need to have two message structures, | | 68 | * To make a new ring datatype, you need to have two message structures, |
| 69 | * let's say request_t, and response_t already defined. | | 69 | * let's say request_t, and response_t already defined. |
| 70 | * | | 70 | * |
| 71 | * In a header where you want the ring datatype declared, you then do: | | 71 | * In a header where you want the ring datatype declared, you then do: |
| 72 | * | | 72 | * |
| 73 | * DEFINE_RING_TYPES(mytag, request_t, response_t); | | 73 | * DEFINE_RING_TYPES(mytag, request_t, response_t); |
| 74 | * | | 74 | * |
| 75 | * These expand out to give you a set of types, as you can see below. | | 75 | * These expand out to give you a set of types, as you can see below. |
| 76 | * The most important of these are: | | 76 | * The most important of these are: |