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- // SPDX-License-Identifier: Apache-2.0
- // SPDX-FileCopyrightText: 2026 The Ebitengine Authors
- //go:build linux
- #include "textflag.h"
- #include "go_asm.h"
- #include "funcdata.h"
- // PPC64LE ELFv2 ABI:
- // - Integer args: R3-R10 (8 registers)
- // - Float args: F1-F8 (8 registers)
- // - Return: R3 (integer), F1 (float)
- // - Stack pointer: R1
- // - Link register: LR (special)
- // - TOC pointer: R2 (must preserve)
- // Stack layout for ELFv2 ABI (aligned to 16 bytes):
- // From callee's perspective when we call BL (CTR):
- // 0(R1) - back chain (our old R1)
- // 8(R1) - CR save word (optional)
- // 16(R1) - LR save (optional, we save it)
- // 24(R1) - Reserved (compilers)
- // 32(R1) - Parameter save area start (8 * 8 = 64 bytes for R3-R10)
- // 96(R1) - First stack arg (a9) - this is where callee looks
- // 104(R1) - Second stack arg (a10)
- // 112-152 - Stack args a11-a15 (5 * 8 = 40 bytes)
- // 160(R1) - TOC save (we put it here, outside param save area)
- // 168(R1) - saved args pointer
- // 176(R1) - padding for 16-byte alignment
- // Total: 176 bytes
- #define STACK_SIZE 176
- #define LR_SAVE 16
- #define TOC_SAVE 160
- #define ARGP_SAVE 168
- GLOBL ·syscall15XABI0(SB), NOPTR|RODATA, $8
- DATA ·syscall15XABI0(SB)/8, $syscall15X(SB)
- TEXT syscall15X(SB), NOSPLIT, $0
- // Prologue: create stack frame
- // R3 contains the args pointer on entry
- MOVD R1, R12 // save old SP
- SUB $STACK_SIZE, R1 // allocate stack frame
- MOVD R12, 0(R1) // save back chain
- MOVD LR, R12
- MOVD R12, LR_SAVE(R1) // save LR
- MOVD R2, TOC_SAVE(R1) // save TOC
- // Save args pointer (in R3)
- MOVD R3, ARGP_SAVE(R1)
- // R11 := args pointer (syscall15Args*)
- MOVD R3, R11
- // Load float args into F1-F8
- FMOVD syscall15Args_f1(R11), F1
- FMOVD syscall15Args_f2(R11), F2
- FMOVD syscall15Args_f3(R11), F3
- FMOVD syscall15Args_f4(R11), F4
- FMOVD syscall15Args_f5(R11), F5
- FMOVD syscall15Args_f6(R11), F6
- FMOVD syscall15Args_f7(R11), F7
- FMOVD syscall15Args_f8(R11), F8
- // Load integer args into R3-R10
- MOVD syscall15Args_a1(R11), R3
- MOVD syscall15Args_a2(R11), R4
- MOVD syscall15Args_a3(R11), R5
- MOVD syscall15Args_a4(R11), R6
- MOVD syscall15Args_a5(R11), R7
- MOVD syscall15Args_a6(R11), R8
- MOVD syscall15Args_a7(R11), R9
- MOVD syscall15Args_a8(R11), R10
- // Spill a9-a15 onto the stack (stack parameters start at 96(R1))
- // Per ELFv2: parameter save area is 32-95, stack args start at 96
- MOVD ARGP_SAVE(R1), R11 // reload args pointer
- MOVD syscall15Args_a9(R11), R12
- MOVD R12, 96(R1) // a9 at 96(R1)
- MOVD syscall15Args_a10(R11), R12
- MOVD R12, 104(R1) // a10 at 104(R1)
- MOVD syscall15Args_a11(R11), R12
- MOVD R12, 112(R1) // a11 at 112(R1)
- MOVD syscall15Args_a12(R11), R12
- MOVD R12, 120(R1) // a12 at 120(R1)
- MOVD syscall15Args_a13(R11), R12
- MOVD R12, 128(R1) // a13 at 128(R1)
- MOVD syscall15Args_a14(R11), R12
- MOVD R12, 136(R1) // a14 at 136(R1)
- MOVD syscall15Args_a15(R11), R12
- MOVD R12, 144(R1) // a15 at 144(R1)
- // Call function: load fn and call
- MOVD syscall15Args_fn(R11), R12
- MOVD R12, CTR
- BL (CTR)
- // Restore TOC after call
- MOVD TOC_SAVE(R1), R2
- // Restore args pointer for storing results
- MOVD ARGP_SAVE(R1), R11
- // Store integer results back (R3, R4)
- MOVD R3, syscall15Args_a1(R11)
- MOVD R4, syscall15Args_a2(R11)
- // Store float return values (F1-F4)
- FMOVD F1, syscall15Args_f1(R11)
- FMOVD F2, syscall15Args_f2(R11)
- FMOVD F3, syscall15Args_f3(R11)
- FMOVD F4, syscall15Args_f4(R11)
- // Epilogue: restore and return
- MOVD LR_SAVE(R1), R12
- MOVD R12, LR
- ADD $STACK_SIZE, R1
- RET
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