compiler_rt: Tracking Issue ARM Routines

[matu3ba]

Context and Purpose

Based on https://gist.github.com/harieamjari/61aa4420ae4ded5e86f5143e46d93573 by user @harieamjari the list of ARM run-time functions to double-check

The official documentation is found here https://github.com/ARM-software/abi-aa/releases and the runtime abi (Q32022) here: https://github.com/ARM-software/abi-aa/blob/2982a9f3b512a5bfdc9e3fea5d3b298f9165c36b/rtabi32/rtabi32.rst

Preparation for audit of compiler_rt in #1504. see also https://embeddedartistry.com/blog/2017/10/11/demystifying-arm-floating-point-compiler-options/

List of Routines

The functions declared here is based on the document, number,
 * "ARM IHI 0043D, current through ABI release 2.09", which
 * defines the run-time helper-function ABI for programs written
 * in ARM-Thumb assembly language, C, and C++.

/ Standard double precision floating-point arithmetic helper functions /

• [x] extern double __aeabi_dadd(double, double);
• [x] extern double __aeabi_ddiv(double n, double d);
• [x] extern double __aeabi_dmul(double, double);
• [x] extern double __aeabi_drsub(double x, double y);
• [x] extern double __aeabi_dsub(double x, double y);

/ double precision floating-point comparison helper functions /

• [ ] extern void __aeabi_cdcmpeq(double, double);
• [ ] extern void __aeabi_cdcmple(double, double);
• [ ] extern void __aeabi_cdrcmple(double, double);
• [x] extern int __aeabi_dcmpeq(double, double);
• [x] extern int __aeabi_dcmplt(double, double);
• [x] extern int __aeabi_dcmple(double, double);
• [x] extern int __aeabi_dcmpge(double, double); TODO README
• [x] extern int __aeabi_dcmpgt(double, double); TODO README
• [x] extern int __aeabi_dcmpun(double, double);

/ Standard single precision floating-point arithmetic helper functions /

• [x] extern float __aeabi_fadd(float, float);
• [x] extern float __aeabi_fdiv(float n, float d);
• [ ] extern float __aeabi_fmul(float, float); TODO README
• [ ] extern float __aeabi_frsub(float x, float y);
• [x] extern float __aeabi_fsub(float x, float y);

/ Standard single precision floating-point comparison helper functions /

• [ ] extern void __aeabi_cfcmpeq(float, float);
• [ ] extern void __aeabi_cfcmple(float, float);
• [ ] extern void __aeabi_cfrcmple(float, float);
• [x] extern int __aeabi_fcmpeq(float, float);
• [x] extern int __aeabi_fcmplt(float, float);
• [x] extern int __aeabi_fcmple(float, float);
• [ ] extern int __aeabi_fcmpge(float, float); TODO README
• [ ] extern int __aeabi_fcmpgt(float, float); TODO README
• [x] extern int __aeabi_fcmpun(float, float);

/ Standard floating-point to integer conversions /

• [x] extern int __aeabi_d2iz(double); TODO README
• [x] extern unsigned __aeabi_d2uiz(double); TODO README
• [x] extern long long __aeabi_d2lz(double); TODO README
• [x] extern unsigned long long __aeabi_d2ulz(double); TODO README
• [x] extern int __aeabi_f2iz(float); TODO README
• [x] extern unsigned __aeabi_f2uiz(float); TODO README
• [x] extern long long __aeabi_f2lz(float); TODO README
• [x] extern unsigned long long __aeabi_f2ulz(float); TODO README

/ Standard conversions between floating types /

• [x] extern float __aeabi_d2f(double);
• [x] extern double __aeabi_f2d(float); TODO README
• [x] extern float __aeabi_h2f(short hf); TODO README
• [ ] extern float __aeabi_h2f_alt(short hf);
• [x] extern short __aeabi_f2h(float f);
• [ ] extern short __aeabi_f2h_alt(float f);
• [x] extern short __aeabi_d2h(double);
• [ ] extern short __aeabi_d2h_alt(double);

/ Standard integer to floating-point conversions /

• [x] extern double __aeabi_i2d(int); TODO README
• [x] extern double __aeabi_ui2d(unsigned); TODO README
• [x] extern double __aeabi_l2d(long long); TODO README
• [x] extern double __aeabi_ul2d(unsigned long long); TODO README
• [x] extern float __aeabi_i2f(int); TODO README
• [x] extern float __aeabi_ui2f(unsigned); TODO README
• [x] extern float __aeabi_l2f(long long); TODO README
• [x] extern float __aeabi_ul2f(unsigned long long); TODO README

/ Long long functions /

• [x] extern long long __aeabi_lmul(long long, long long); TODO README
• [x] extern lldiv_t __aeabi_ldivmod(long long n, long long d); TODO README / ulldiv_t might be unsupported /
• [x] extern ulldiv_t __aeabi_uldivmod(unsigned long long n, unsigned long long d); TODO README
• [x] extern long long __aeabi_llsl(long long, int);
• [x] extern long long __aeabi_llsr(long long, int);
• [ ] extern int __aeabi_lcmp(long long, long long);
• [ ] extern int __aeabi_ulcmp(unsigned long long, unsigned long long);

/ Integer (32/32 -> 32) division functions /

• [x] extern int __aeabi_idiv(int numerator, int denominator);
• [x] extern unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator); typedef struct { int quot; int rem; } idiv_return; typedef struct { unsigned quot; unsigned rem; } uidiv_return;
• [x] extern idiv_return __aeabi_idivmod(int numerator, int denominator); TODO README
• [x] extern uidiv_return __aeabi_uidivmod(unsigned numerator, unsigned denominator); TODO README

/ Division by zero /

• [ ] extern int __aeabi_idiv0(int return_value);
• [ ] extern long long __aeabi_ldiv0(long long return_value);

/ Unaligned memory access /

• [ ] extern int __aeabi_uread4(void *address);
• [ ] extern int __aeabi_uwrite4(int value, void *address);
• [ ] extern long long __aeabi_uread8(void *address);
• [ ] extern long long __aeabi_uwrite8(long long value, void *address);

/ Memory copying /

• [x] extern void __aeabi_memcpy8(void dest, const void src, size_t n);
• [x] extern void __aeabi_memcpy4(void dest, const void src, size_t n);
• [x] extern void __aeabi_memcpy(void dest, const void src, size_t n);
• [x] extern void __aeabi_memmove8(void dest, const void src, size_t n);
• [x] extern void __aeabi_memmove4(void dest, const void src, size_t n);
• [x] extern void __aeabi_memmove(void dest, const void src, size_t n);

/ Memory clearing and setting /

• [x] extern void __aeabi_memset8(void *dest, size_t n, int c);
• [x] extern void __aeabi_memset4(void *dest, size_t n, int c);
• [x] extern void __aeabi_memset(void *dest, size_t n, int c);
• [x] extern void __aeabi_memclr8(void *dest, size_t n);
• [x] extern void __aeabi_memclr4(void *dest, size_t n);
• [x] extern void __aeabi_memclr(void *dest, size_t n);

[matu3ba]

See also #15468.

[matu3ba]

ARM-only ones:	Done	Name	a	b	Out	Comment
					Float Comparison
✗	__aeabi_cfcmpeq	f32	f32	void	a == b result in PSR ZC flags[^PSRZC]
✗	__aeabi_cfcmple	f32	f32	void	a <= b result ..
✗	__aeabi_cfrcmple	f32	f32	void	b <= a ..
✗	__aeabi_cdcmpeq	f64	f64	void	a == b ..
✗	__aeabi_cdcmple	f64	f64	void	a <= b ..
✗	__aeabi_cdrcmple	f64	f64	void	b <= a ..
					Float Arithmetic
✗	__aeabi_frsub	f64	f64	f64	b - a
✗	__aeabi_drsub	f64	f64	f64	..
					Special
✓	__aeabi_read_tp	∅	∅	*u8	ret tls pointer
✗	__aeabi_idiv0	i32	∅	i32	div by 0 modifier
✗	__aeabi_ldiv0	i64	∅	i64	div by 0 modifier
					Unaligned memory access
✗	__aeabi_uread4	[*]u8	∅	i32	ret value read
✗	__aeabi_uwrite4	i32	[*]u8	i32	ret value written
✗	__aeabi_uread8	[*]u8	∅	i64	..
✗	__aeabi_uwrite8	i64	[*]u8	i64	..

Done	Name	a	b	c	Comment
					Memory copy, move and set
✓	__aeabi_memcpy8	[*]u8	[*]u8	usize	dest, src, size
✓	__aeabi_memcpy4	[*]u8	[*]u8	usize	..
✓	__aeabi_memcpy	[*]u8	[*]u8	usize	..
✓	__aeabi_memmove8	[*]u8	[*]u8	usize	dest, src, size
✓	__aeabi_memmove4	[*]u8	[*]u8	usize	..
✓	__aeabi_memmove	[*]u8	[*]u8	usize	..
✓	__aeabi_memset8	[*]u8	usize	i32	*dest, size, char
✓	__aeabi_memset4	[*]u8	usize	i32	..
✓	__aeabi_memset	[*]u8	usize	i32	..
✓	__aeabi_memclr8	[*]u8	u32	usize	*dest, size
✓	__aeabi_memclr4	[*]u8	u32	usize	..
✓	__aeabi_memclr	[*]u8	u32	usize	..
✓	__aeabi_uwrite8	i64	[*]u8	i64	..

Note: If having identical implementation [including besides function signature], routines are documented in #15675 and #15676.