diff options
Diffstat (limited to 'coroutine/ppc')
| -rw-r--r-- | coroutine/ppc/Context.S | 90 | ||||
| -rw-r--r-- | coroutine/ppc/Context.h | 58 |
2 files changed, 148 insertions, 0 deletions
diff --git a/coroutine/ppc/Context.S b/coroutine/ppc/Context.S new file mode 100644 index 0000000000..e2431a9250 --- /dev/null +++ b/coroutine/ppc/Context.S @@ -0,0 +1,90 @@ +; Based on the code by Samuel Williams. Created by Sergey Fedorov on 04/06/2022. +; Credits to Samuel Williams, Rei Odaira and Iain Sandoe. Errors, if any, are mine. +; Some relevant examples: https://github.com/gcc-mirror/gcc/blob/master/libphobos/libdruntime/config/powerpc/switchcontext.S +; https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/rs6000/darwin-gpsave.S +; https://www.ibm.com/docs/en/aix/7.2?topic=epilogs-saving-gprs-only +; ppc32 version may be re-written compactly with stmw/lwm, but the code won't be faster, see: https://github.com/ruby/ruby/pull/5927#issuecomment-1139730541 + +; Notice that this code is only for Darwin (macOS). Darwin ABI differs from AIX and ELF. +; To add support for AIX, *BSD or *Linux, please make separate implementations. + +#define TOKEN_PASTE(x,y) x##y +#define PREFIXED_SYMBOL(prefix,name) TOKEN_PASTE(prefix,name) + +.machine ppc7400 ; = G4, Rosetta +.text + +.globl PREFIXED_SYMBOL(SYMBOL_PREFIX,coroutine_transfer) +.align 2 + +PREFIXED_SYMBOL(SYMBOL_PREFIX,coroutine_transfer): + ; Make space on the stack for caller registers + ; (Should we rather use red zone? See libphobos example.) + subi r1,r1,80 + + ; Get LR + mflr r0 + + ; Save caller registers + stw r31,0(r1) + stw r30,4(r1) + stw r29,8(r1) + stw r28,12(r1) + stw r27,16(r1) + stw r26,20(r1) + stw r25,24(r1) + stw r24,28(r1) + stw r23,32(r1) + stw r22,36(r1) + stw r21,40(r1) + stw r20,44(r1) + stw r19,48(r1) + stw r18,52(r1) + stw r17,56(r1) + stw r16,60(r1) + stw r15,64(r1) + stw r14,68(r1) + stw r13,72(r1) + + ; Save return address + ; Possibly should rather be saved into linkage area, see libphobos and IBM docs + stw r0,76(r1) + + ; Save stack pointer to first argument + stw r1,0(r3) + + ; Load stack pointer from second argument + lwz r1,0(r4) + + ; Load return address + lwz r0,76(r1) + + ; Restore caller registers + lwz r13,72(r1) + lwz r14,68(r1) + lwz r15,64(r1) + lwz r16,60(r1) + lwz r17,56(r1) + lwz r18,52(r1) + lwz r19,48(r1) + lwz r20,44(r1) + lwz r21,40(r1) + lwz r22,36(r1) + lwz r23,32(r1) + lwz r24,28(r1) + lwz r25,24(r1) + lwz r26,20(r1) + lwz r27,16(r1) + lwz r28,12(r1) + lwz r29,8(r1) + lwz r30,4(r1) + lwz r31,0(r1) + + ; Set LR + mtlr r0 + + ; Pop stack frame + addi r1,r1,80 + + ; Jump to return address + blr diff --git a/coroutine/ppc/Context.h b/coroutine/ppc/Context.h new file mode 100644 index 0000000000..8035d08556 --- /dev/null +++ b/coroutine/ppc/Context.h @@ -0,0 +1,58 @@ +#ifndef COROUTINE_PPC_CONTEXT_H +#define COROUTINE_PPC_CONTEXT_H 1 + +#pragma once + +#include <assert.h> +#include <stddef.h> +#include <stdint.h> +#include <string.h> + +#define COROUTINE __attribute__((noreturn)) void +#define COROUTINE_LIMITED_ADDRESS_SPACE + +enum { + COROUTINE_REGISTERS = + 20 /* 19 general purpose registers (r13-r31) and 1 return address */ + + 4 /* space for fiber_entry() to store the link register */ +}; + +struct coroutine_context +{ + void **stack_pointer; + void *argument; +}; + +typedef COROUTINE(* coroutine_start)(struct coroutine_context *from, struct coroutine_context *self); + +static inline void coroutine_initialize_main(struct coroutine_context * context) { + context->stack_pointer = NULL; +} + +static inline void coroutine_initialize( + struct coroutine_context *context, + coroutine_start start, + void *stack, + size_t size +) { + assert(start && stack && size >= 1024); + + // Stack grows down. Force 16-byte alignment. + char * top = (char*)stack + size; + context->stack_pointer = (void**)((uintptr_t)top & ~0xF); + + context->stack_pointer -= COROUTINE_REGISTERS; + memset(context->stack_pointer, 0, sizeof(void*) * COROUTINE_REGISTERS); + + /* Skip a global prologue that sets the TOC register */ + context->stack_pointer[19] = ((char*)start) + 8; +} + +struct coroutine_context * coroutine_transfer(struct coroutine_context * current, struct coroutine_context * target); + +static inline void coroutine_destroy(struct coroutine_context * context) +{ + context->stack_pointer = NULL; +} + +#endif /* COROUTINE_PPC_CONTEXT_H */ |