diff options
Diffstat (limited to 'src/runtime/asm_riscv64.s')
| -rw-r--r-- | src/runtime/asm_riscv64.s | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/src/runtime/asm_riscv64.s b/src/runtime/asm_riscv64.s index 31b81aea12..4c434ea551 100644 --- a/src/runtime/asm_riscv64.s +++ b/src/runtime/asm_riscv64.s @@ -714,10 +714,10 @@ TEXT ·unspillArgs(SB),NOSPLIT,$0-0 // gcWriteBarrier performs a heap pointer write and informs the GC. // -// gcWriteBarrier does NOT follow the Go ABI. It takes two arguments: -// - T0 is the destination of the write -// - T1 is the value being written at T0. -// It clobbers R30 (the linker temp register - REG_TMP). +// gcWriteBarrier does NOT follow the Go ABI. It accepts the +// number of bytes of buffer needed in X24, and returns a pointer +// to the buffer spcae in X24. +// It clobbers X31 aka T6 (the linker temp register - REG_TMP). // The act of CALLing gcWriteBarrier will clobber RA (LR). // It does not clobber any other general-purpose registers, // but may clobber others (e.g., floating point registers). @@ -725,21 +725,21 @@ TEXT runtime·gcWriteBarrier<ABIInternal>(SB),NOSPLIT,$208 // Save the registers clobbered by the fast path. MOV A0, 24*8(X2) MOV A1, 25*8(X2) +retry: MOV g_m(g), A0 MOV m_p(A0), A0 MOV (p_wbBuf+wbBuf_next)(A0), A1 + MOV (p_wbBuf+wbBuf_end)(A0), T6 // T6 is linker temp register (REG_TMP) // Increment wbBuf.next position. ADD $16, A1 + // Is the buffer full? + BLTU T6, A1, flush + // Commit to the larger buffer. MOV A1, (p_wbBuf+wbBuf_next)(A0) - MOV (p_wbBuf+wbBuf_end)(A0), A0 - MOV A0, T6 // T6 is linker temp register (REG_TMP) // Record the write. MOV T1, -16(A1) // Record value MOV (T0), A0 // TODO: This turns bad writes into bad reads. MOV A0, -8(A1) // Record *slot - // Is the buffer full? - BEQ A1, T6, flush -ret: MOV 24*8(X2), A0 MOV 25*8(X2), A1 // Do the write. @@ -749,15 +749,13 @@ ret: flush: // Save all general purpose registers since these could be // clobbered by wbBufFlush and were not saved by the caller. - MOV T0, 1*8(X2) // Also first argument to wbBufFlush - MOV T1, 2*8(X2) // Also second argument to wbBufFlush + MOV T0, 1*8(X2) + MOV T1, 2*8(X2) // X0 is zero register // X1 is LR, saved by prologue // X2 is SP // X3 is GP // X4 is TP - // X5 is first arg to wbBufFlush (T0) - // X6 is second arg to wbBufFlush (T1) MOV X7, 3*8(X2) MOV X8, 4*8(X2) MOV X9, 5*8(X2) @@ -784,7 +782,6 @@ flush: MOV X30, 23*8(X2) // X31 is tmp register. - // This takes arguments T0 and T1. CALL runtime·wbBufFlush(SB) MOV 1*8(X2), T0 @@ -811,7 +808,7 @@ flush: MOV 22*8(X2), X29 MOV 23*8(X2), X30 - JMP ret + JMP retry // Note: these functions use a special calling convention to save generated code space. // Arguments are passed in registers (ssa/gen/RISCV64Ops.go), but the space for those |