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Diffstat (limited to 'tinyusb/lib/SEGGER_RTT/RTT/SEGGER_RTT_ASM_ARMv7M.S')
| -rwxr-xr-x | tinyusb/lib/SEGGER_RTT/RTT/SEGGER_RTT_ASM_ARMv7M.S | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/tinyusb/lib/SEGGER_RTT/RTT/SEGGER_RTT_ASM_ARMv7M.S b/tinyusb/lib/SEGGER_RTT/RTT/SEGGER_RTT_ASM_ARMv7M.S new file mode 100755 index 00000000..78cde4d7 --- /dev/null +++ b/tinyusb/lib/SEGGER_RTT/RTT/SEGGER_RTT_ASM_ARMv7M.S @@ -0,0 +1,235 @@ +/********************************************************************* +* (c) SEGGER Microcontroller GmbH * +* The Embedded Experts * +* www.segger.com * +********************************************************************** + +-------------------------- END-OF-HEADER ----------------------------- + +File : SEGGER_RTT_ASM_ARMv7M.S +Purpose : Assembler implementation of RTT functions for ARMv7M + +Additional information: + This module is written to be assembler-independent and works with + GCC and clang (Embedded Studio) and IAR. +*/ + +#define SEGGER_RTT_ASM // Used to control processed input from header file +#include "SEGGER_RTT.h" + +/********************************************************************* +* +* Defines, fixed +* +********************************************************************** +*/ +#define _CCIAR 0 +#define _CCCLANG 1 + +#if (defined __SES_ARM) || (defined __GNUC__) || (defined __clang__) + #define _CC_TYPE _CCCLANG + #define _PUB_SYM .global + #define _EXT_SYM .extern + #define _END .end + #define _WEAK .weak + #define _THUMB_FUNC .thumb_func + #define _THUMB_CODE .code 16 + #define _WORD .word + #define _SECTION(Sect, Type, AlignExp) .section Sect ##, "ax" + #define _ALIGN(Exp) .align Exp + #define _PLACE_LITS .ltorg + #define _DATA_SECT_START + #define _C_STARTUP _start + #define _STACK_END __stack_end__ + #define _RAMFUNC + // + // .text => Link to flash + // .fast => Link to RAM + // OtherSect => Usually link to RAM + // Alignment is 2^x + // +#elif defined (__IASMARM__) + #define _CC_TYPE _CCIAR + #define _PUB_SYM PUBLIC + #define _EXT_SYM EXTERN + #define _END END + #define _WEAK _WEAK + #define _THUMB_FUNC + #define _THUMB_CODE THUMB + #define _WORD DCD + #define _SECTION(Sect, Type, AlignExp) SECTION Sect ## : ## Type ## :REORDER:NOROOT ## (AlignExp) + #define _ALIGN(Exp) alignrom Exp + #define _PLACE_LITS + #define _DATA_SECT_START DATA + #define _C_STARTUP __iar_program_start + #define _STACK_END sfe(CSTACK) + #define _RAMFUNC SECTION_TYPE SHT_PROGBITS, SHF_WRITE | SHF_EXECINSTR + // + // .text => Link to flash + // .textrw => Link to RAM + // OtherSect => Usually link to RAM + // NOROOT => Allows linker to throw away the function, if not referenced + // Alignment is 2^x + // +#endif + +#if (_CC_TYPE == _CCIAR) + NAME SEGGER_RTT_ASM_ARMv7M +#else + .syntax unified +#endif + +#if defined (RTT_USE_ASM) && (RTT_USE_ASM == 1) + #define SHT_PROGBITS 0x1 + +/********************************************************************* +* +* Public / external symbols +* +********************************************************************** +*/ + + _EXT_SYM __aeabi_memcpy + _EXT_SYM __aeabi_memcpy4 + _EXT_SYM _SEGGER_RTT + + _PUB_SYM SEGGER_RTT_ASM_WriteSkipNoLock + +/********************************************************************* +* +* SEGGER_RTT_WriteSkipNoLock +* +* Function description +* Stores a specified number of characters in SEGGER RTT +* control block which is then read by the host. +* SEGGER_RTT_WriteSkipNoLock does not lock the application and +* skips all data, if the data does not fit into the buffer. +* +* Parameters +* BufferIndex Index of "Up"-buffer to be used (e.g. 0 for "Terminal"). +* pBuffer Pointer to character array. Does not need to point to a \0 terminated string. +* NumBytes Number of bytes to be stored in the SEGGER RTT control block. +* MUST be > 0!!! +* This is done for performance reasons, so no initial check has do be done. +* +* Return value +* 1: Data has been copied +* 0: No space, data has not been copied +* +* Notes +* (1) If there is not enough space in the "Up"-buffer, all data is dropped. +* (2) For performance reasons this function does not call Init() +* and may only be called after RTT has been initialized. +* Either by calling SEGGER_RTT_Init() or calling another RTT API function first. +*/ + _SECTION(.text, CODE, 2) + _ALIGN(2) + _THUMB_FUNC +SEGGER_RTT_ASM_WriteSkipNoLock: // unsigned SEGGER_RTT_WriteSkipNoLock(unsigned BufferIndex, const void* pData, unsigned NumBytes) { + // + // Cases: + // 1) RdOff <= WrOff => Space until wrap-around is sufficient + // 2) RdOff <= WrOff => Space after wrap-around needed (copy in 2 chunks) + // 3) RdOff < WrOff => No space in buf + // 4) RdOff > WrOff => Space is sufficient + // 5) RdOff > WrOff => No space in buf + // + // 1) is the most common case for large buffers and assuming that J-Link reads the data fast enough + // + // Register usage: + // R0 Temporary needed as RdOff, <Tmp> register later on + // R1 pData + // R2 <NumBytes> + // R3 <Tmp> register. Hold free for subroutine calls + // R4 <Rem> + // R5 pRing->pBuffer + // R6 pRing (Points to active struct SEGGER_RTT_BUFFER_DOWN) + // R7 WrOff + // + PUSH {R4-R7} + ADD R3,R0,R0, LSL #+1 + LDR.W R0,=_SEGGER_RTT // pRing = &_SEGGER_RTT.aUp[BufferIndex]; + ADD R0,R0,R3, LSL #+3 + ADD R6,R0,#+24 + LDR R0,[R6, #+16] // RdOff = pRing->RdOff; + LDR R7,[R6, #+12] // WrOff = pRing->WrOff; + LDR R5,[R6, #+4] // pRing->pBuffer + CMP R7,R0 + BCC.N _CheckCase4 // if (RdOff <= WrOff) { => Case 1), 2) or 3) + // + // Handling for case 1, later on identical to case 4 + // + LDR R3,[R6, #+8] // Avail = pRing->SizeOfBuffer - WrOff - 1u; => Space until wrap-around (assume 1 byte not usable for case that RdOff == 0) + SUBS R4,R3,R7 // <Rem> (Used in case we jump into case 2 afterwards) + SUBS R3,R4,#+1 // <Avail> + CMP R3,R2 + BCC.N _CheckCase2 // if (Avail >= NumBytes) { => Case 1)? +_Case4: + ADDS R5,R7,R5 // pBuffer += WrOff + ADDS R0,R2,R7 // v = WrOff + NumBytes + // + // 2x unrolling for the copy loop that is used most of the time + // This is a special optimization for small SystemView packets and makes them even faster + // + _ALIGN(2) +_LoopCopyStraight: // memcpy(pRing->pBuffer + WrOff, pData, NumBytes); + LDRB R3,[R1], #+1 + STRB R3,[R5], #+1 // *pDest++ = *pSrc++ + SUBS R2,R2,#+1 + BEQ _CSDone + LDRB R3,[R1], #+1 + STRB R3,[R5], #+1 // *pDest++ = *pSrc++ + SUBS R2,R2,#+1 + BNE _LoopCopyStraight +_CSDone: + STR R0,[R6, #+12] // pRing->WrOff = WrOff + NumBytes; + MOVS R0,#+1 + POP {R4-R7} + BX LR // Return 1 +_CheckCase2: + ADDS R0,R0,R3 // Avail += RdOff; => Space incl. wrap-around + CMP R0,R2 + BCC.N _Case3 // if (Avail >= NumBytes) { => Case 2? => If not, we have case 3) (does not fit) + // + // Handling for case 2 + // + ADDS R0,R7,R5 // v = pRing->pBuffer + WrOff => Do not change pRing->pBuffer here because 2nd chunk needs org. value + SUBS R2,R2,R4 // NumBytes -= Rem; (Rem = pRing->SizeOfBuffer - WrOff; => Space until end of buffer) +_LoopCopyBeforeWrapAround: // memcpy(pRing->pBuffer + WrOff, pData, Rem); => Copy 1st chunk + LDRB R3,[R1], #+1 + STRB R3,[R0], #+1 // *pDest++ = *pSrc++ + SUBS R4,R4,#+1 + BNE _LoopCopyBeforeWrapAround + // + // Special case: First check that assumed RdOff == 0 calculated that last element before wrap-around could not be used + // But 2nd check (considering space until wrap-around and until RdOff) revealed that RdOff is not 0, so we can use the last element + // In this case, we may use a copy straight until buffer end anyway without needing to copy 2 chunks + // Therefore, check if 2nd memcpy is necessary at all + // + ADDS R4,R2,#+0 // Save <NumBytes> (needed as counter in loop but must be written to <WrOff> after the loop). Also use this inst to update the flags to skip 2nd loop if possible + BEQ.N _No2ChunkNeeded // if (NumBytes) { +_LoopCopyAfterWrapAround: // memcpy(pRing->pBuffer, pData + Rem, NumBytes); + LDRB R3,[R1], #+1 // pData already points to the next src byte due to copy loop increment before this loop + STRB R3,[R5], #+1 // *pDest++ = *pSrc++ + SUBS R2,R2,#+1 + BNE _LoopCopyAfterWrapAround +_No2ChunkNeeded: + STR R4,[R6, #+12] // pRing->WrOff = NumBytes; => Must be written after copying data because J-Link may read control block asynchronously while writing into buffer + MOVS R0,#+1 + POP {R4-R7} + BX LR // Return 1 +_CheckCase4: + SUBS R0,R0,R7 + SUBS R0,R0,#+1 // Avail = RdOff - WrOff - 1u; + CMP R0,R2 + BCS.N _Case4 // if (Avail >= NumBytes) { => Case 4) == 1) ? => If not, we have case 5) == 3) (does not fit) +_Case3: + MOVS R0,#+0 + POP {R4-R7} + BX LR // Return 0 + _PLACE_LITS + +#endif // defined (RTT_USE_ASM) && (RTT_USE_ASM == 1) + _END + +/*************************** End of file ****************************/ |