| /* |
| * Copyright (c) 2020 Raspberry Pi (Trading) Ltd. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| #include <string.h> |
| #include "pico/bootrom.h" |
| #include "pico/bootrom/sf_table.h" |
| |
| // NOTE THIS FUNCTION TABLE IS NOT PUBLIC OR NECESSARILY COMPLETE... |
| // IT IS ***NOT*** SAFE TO CALL THESE FUNCTION POINTERS FROM ARBITRARY CODE |
| uint32_t sf_table[SF_TABLE_V2_SIZE / 2]; |
| void __attribute__((weak)) *sf_clz_func; |
| |
| #if !(PICO_FLOAT_SUPPORT_ROM_V1 && PICO_RP2040_B0_SUPPORTED) |
| static __attribute__((noreturn)) void missing_float_func_shim(void) { |
| panic(""); |
| } |
| #endif |
| |
| void __aeabi_float_init(void) { |
| int rom_version = rp2040_rom_version(); |
| void *rom_table = rom_data_lookup(rom_table_code('S', 'F')); |
| #if PICO_FLOAT_SUPPORT_ROM_V1 && PICO_RP2040_B0_SUPPORTED |
| if (rom_version == 1) { |
| memcpy(&sf_table, rom_table, SF_TABLE_V1_SIZE); |
| extern void float_table_shim_on_use_helper(void); |
| // todo replace NDEBUG with a more exclusive assertion guard |
| #ifndef NDEBUG |
| if (*(uint16_t *)0x29ee != 0x0fc4 || // this is packx |
| *(uint16_t *)0x29c0 != 0x0dc2 || // this is upackx |
| *(uint16_t *)0x2b96 != 0xb5c0 || // this is cordic_vec |
| *(uint16_t *)0x2b18 != 0x2500 || // this is packretns |
| *(uint16_t *)0x2acc != 0xb510 || // this is float2fix |
| *(uint32_t *)0x2cfc != 0x6487ed51 // pi_q29 |
| ) { |
| panic(""); |
| } |
| #endif |
| |
| // this is a little tricky.. we only want to pull in a shim if the corresponding function |
| // is called. to that end we include a SVC instruction with the table offset as the call number |
| // followed by the shim function pointer inside the actual wrapper function. that way if the wrapper |
| // function is garbage collected, so is the shim function. |
| // |
| // float_table_shim_on_use_helper expects this SVC instruction in the calling code soon after the address |
| // pointed to by IP and patches the float_table entry with the real shim the first time the function is called. |
| |
| for(uint i=SF_TABLE_V1_SIZE/4; i<SF_TABLE_V2_SIZE/4; i++) { |
| sf_table[i] = (uintptr_t)float_table_shim_on_use_helper; |
| } |
| // we shim these for -0 and -denormal handling |
| sf_table[SF_TABLE_FLOAT2INT/4] = sf_table[SF_TABLE_FLOAT2FIX/4] = (uintptr_t)float_table_shim_on_use_helper; |
| } |
| #else |
| if (rom_version == 1) { |
| memcpy(&sf_table, rom_table, SF_TABLE_V1_SIZE); |
| // opting for soft failure for now - you'll get a panic at runtime if you call any of the missing methods |
| for(uint i=0;i<SF_TABLE_V2_SIZE/4;i++) { |
| if (!sf_table[i]) sf_table[i] = (uintptr_t)missing_float_func_shim; |
| } |
| } |
| #endif |
| if (rom_version >= 2) { |
| assert(*((uint8_t *)rom_table-2) * 4 >= SF_TABLE_V2_SIZE); |
| memcpy(&sf_table, rom_table, SF_TABLE_V2_SIZE); |
| } |
| sf_clz_func = rom_func_lookup(ROM_FUNC_CLZ32); |
| } |