Initial Release

src/rp2_common/pico_bit_ops/bit_ops_aeabi.S

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+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+.syntax unified
+.cpu cortex-m0plus
+.thumb
+
+#include "pico/asm_helper.S"
+__pre_init __aeabi_bits_init, 00010
+
+.macro bits_section name
+#if PICO_BITS_IN_RAM
+.section RAM_SECTION_NAME(\name), "ax"
+#else
+.section SECTION_NAME(\name), "ax"
+#endif
+.endm
+
+.section .data.aeabi_bits_funcs
+.global aeabi_bits_funcs, aeabi_bits_funcs_end
+.equ BITS_FUNC_COUNT, 4
+.align 4
+aeabi_bits_funcs:
+    .word rom_table_code('P','3') // popcount32
+    .word rom_table_code('L','3') // clz32
+    .word rom_table_code('T','3') // ctz32
+    .word rom_table_code('R','3') // reverse32
+aeabi_bits_funcs_end:
+
+.section .text
+.thumb_func
+__aeabi_bits_init:
+    ldr r0, =aeabi_bits_funcs
+    movs r1, #BITS_FUNC_COUNT
+    ldr r3, =rom_funcs_lookup
+    bx r3
+
+.equ POPCOUNT32, 0
+.equ CLZ32, 4
+.equ CTZ32, 8
+.equ REVERSE32, 12
+
+bits_section clzsi
+wrapper_func __clz
+wrapper_func __clzl
+wrapper_func __clzsi2
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #CLZ32]
+    bx r3
+
+bits_section ctzsi
+wrapper_func __ctzsi2
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #CTZ32]
+    bx r3
+
+bits_section popcountsi
+wrapper_func __popcountsi2
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #POPCOUNT32]
+    bx r3
+
+bits_section clzdi
+wrapper_func __clzll
+wrapper_func __clzdi2
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #CLZ32]
+    cmp r1, #0
+    bne 1f
+    push {lr}
+    blx r3
+    adds r0, #32
+    pop {pc}
+1:
+    mov r0, r1
+    bx r3
+
+bits_section ctzdi
+wrapper_func __ctzdi2
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #CTZ32]
+    cmp r0, #0
+    bne 1f
+    bx r3
+1:
+    push {lr}
+    mov r0, r1
+    blx r3
+    adds r0, #32
+    pop {pc}
+
+bits_section popcountdi
+wrapper_func __popcountdi2
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #POPCOUNT32]
+    push {r1, r3, lr}
+    blx r3
+    mov ip, r0
+    pop {r0, r3}
+    blx r3
+    mov r1, ip
+    add r0, r1
+    pop {pc}
+
+bits_section reverse32
+regular_func reverse32
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #REVERSE32]
+    bx r3
+
+bits_section __rev
+regular_func __rev
+regular_func __revl
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #REVERSE32]
+    bx r3
+
+bits_section __revll
+regular_func __revll
+    push {lr}
+    ldr r3, =aeabi_bits_funcs
+    ldr r3, [r3, #REVERSE32]
+    push {r1, r3}
+    blx r3
+    mov ip, r0 // reverse32 preserves ip
+    pop {r0, r3}
+    blx r3
+    mov r1, ip
+    pop {pc}