xref: /aosp_15_r20/art/runtime/interpreter/mterp/riscv64/floating_point.S (revision 795d594fd825385562da6b089ea9b2033f3abf5a)
1// Note: Floating point operations must follow IEEE 754 rules, using round-to-nearest and gradual
2// underflow, except where stated otherwise.
3
4//
5// floating-point comparators vAA, vBB, vCC
6// Note: Perform the indicated floating point comparison, setting a to 0 if b == c, 1 if b > c, or
7// -1 if b < c. The "bias" listed indicates how NaN comparisons are treated: "gt bias" instructions
8// return 1 for NaN comparisons, and "lt bias" instructions return -1.
9//
10
11// cmpl-float vAA, vBB, vCC
12// Format 23x: AA|2d CC|BB
13// LT bias, if NaN then vAA := -1
14%def op_cmpl_float(is_double=False):
15   FETCH t1, count=1     // t1 := CC|BB
16   srliw t0, xINST, 8    // t0 := AA
17   srliw t2, t1, 8       // t2 := CC
18   andi t1, t1, 0xFF     // t1 := BB
19%  get_vreg_float("ft1", "t1", is_double=is_double)  # ft1 := fp[BB]
20%  get_vreg_float("ft2", "t2", is_double=is_double)  # ft2 := fp[CC]
21   // Note: Formula "((FLE r,l) - 1) + (FLT r,l)" lifted from compiler.
22%  precision = "d" if is_double else "s"
23   fle.${precision} t1, ft2, ft1
24   flt.${precision} t2, ft2, ft1
25   addi t1, t1, -1
26   add t2, t2, t1
27   FETCH_ADVANCE_INST 2
28%  set_vreg("t2", "t0", z0="t1")  # fp[AA] := result
29   GET_INST_OPCODE t0
30   GOTO_OPCODE t0
31
32// cmpg-float vvAA, vBB, vCC
33// Format 23x: AA|2e CC|BB
34// GT bias, if NaN then vAA := 1
35%def op_cmpg_float(is_double=False):
36   FETCH t1, count=1     // t1 := CC|BB
37   srliw t0, xINST, 8    // t0 := AA
38   srliw t2, t1, 8       // t2 := CC
39   andi t1, t1, 0xFF     // t1 := BB
40%  get_vreg_float("ft1", "t1", is_double=is_double)  # ft1 := fp[BB]
41%  get_vreg_float("ft2", "t2", is_double=is_double)  # ft2 := fp[CC]
42   // Note: Formula "((FLE l,r) ^ 1) - (FLT l,r)" lifted from compiler.
43%  precision = "d" if is_double else "s"
44   fle.${precision} t1, ft1, ft2
45   flt.${precision} t2, ft1, ft2
46   xori t1, t1, 1
47   sub t2, t1, t2
48   FETCH_ADVANCE_INST 2
49%  set_vreg("t2", "t0", z0="t1")  # fp[AA] := result
50   GET_INST_OPCODE t0
51   GOTO_OPCODE t0
52
53// cmpl-double vAA, vBB, vCC
54// Format 23x: AA|2f CC|BB
55// LT bias, if NaN then vAA := -1
56%def op_cmpl_double():
57%  op_cmpl_float(is_double=True)
58
59// cmpg-double vAA, vBB, vCC
60// Format 23x: AA|30 CC|BB
61// Note: Formula "((FLE l,r) ^ 1) - (FLT l,r)" lifted from compiler.
62// GT bias, if NaN then vAA := 1
63%def op_cmpg_double():
64%  op_cmpg_float(is_double=True)
65
66//
67// funop vA, vB
68// Format 12x: B|A|op
69//
70
71// neg-float vA, vB
72// Format 12x: B|A|7f
73%def op_neg_float():
74%  generic_funop(instr="fneg.s ft0, ft0", dst="s", src="s")
75
76// neg-double vA, vB
77// Format 12x: B|A|80
78%def op_neg_double():
79%  generic_funop(instr="fneg.d ft0, ft0", dst="d", src="d")
80
81// int-to-float vA, vB
82// Format 12x: B|A|82
83// Note: Conversion of int32 to float, using round-to-nearest. This loses precision for some values.
84// Note: For ties, the IEEE 754-2008 standard defaults to "roundTiesToEven" for binary floats.
85%def op_int_to_float():
86%  generic_funop(instr="fcvt.s.w ft0, t1, rne", dst="s", src="w")
87
88// int-to-double vA, vB
89// Format 12x: B|A|83
90// Note: Conversion of int32 to double.
91%def op_int_to_double():
92%  generic_funop(instr="fcvt.d.w ft0, t1", dst="d", src="w")
93
94// long-to-float vA, vB
95// Format 12x: B|A|85
96// Note: Conversion of int64 to float, using round-to-nearest. This loses precision for some values.
97// Note: For ties, the IEEE 754-2008 standard defaults to "roundTiesToEven" for binary floats.
98%def op_long_to_float():
99%  generic_funop(instr="fcvt.s.l ft0, t1, rne", dst="s", src="l")
100
101// long-to-double vA, vB
102// Format 12x: B|A|86
103// Note: Conversion of int64 to double, using round-to-nearest. This loses precision for some values.
104// Note: For ties, the IEEE 754-2008 standard defaults to "roundTiesToEven" for binary floats.
105%def op_long_to_double():
106%  generic_funop(instr="fcvt.d.l ft0, t1, rne", dst="d", src="l")
107
108// float-to-int vA, vB
109// Format 12x: B|A|87
110// Note: Conversion of float to int32, using round-toward-zero. NaN and -0.0 (negative zero)
111// convert to the integer 0. Infinities and values with too large a magnitude to be represented
112// get converted to either 0x7fffffff or -0x80000000 depending on sign.
113//
114// FCVT.W.S RTZ has the following behavior:
115// - NaN rounds to 0x7ffffff - requires check and set to zero.
116// - negative zero rounds to zero - matches dex spec.
117// - pos inf rounds to 0x7fffffff - matches dex spec.
118// - neg inf rounds to 0x80000000 - matches dex spec.
119%def op_float_to_int():
120%  generic_funop(instr="fcvt.w.s t1, ft0, rtz", dst="w", src="s", nan_zeroed=True)
121
122// float-to-long vA, vB
123// Format 12x: B|A|88
124// Note: Conversion of float to int64, using round-toward-zero. The same special case rules as for
125// float-to-int apply here, except that out-of-range values get converted to either
126// 0x7fffffffffffffff or -0x8000000000000000 depending on sign.
127//
128// FCVT.L.S RTZ has the following behavior:
129// - NaN rounds to 0x7fffffffffffffff - requires check and set to zero.
130// - negative zero rounds to zero - matches dex spec.
131// - pos inf rounds to 0x7fffffffffffffff - matches dex spec.
132// - neg inf rounds to 0x8000000000000000 - matches dex spec.
133%def op_float_to_long():
134%  generic_funop(instr="fcvt.l.s t1, ft0, rtz", dst="l", src="s", nan_zeroed=True)
135
136// float-to-double vA, vB
137// Format 12x: B|A|89
138// Note: Conversion of float to double, preserving the value exactly.
139%def op_float_to_double():
140%  generic_funop(instr="fcvt.d.s ft0, ft0", dst="d", src="s")
141
142// double-to-int vA, vB
143// Format 12x: B|A|8a
144// Note: Conversion of double to int32, using round-toward-zero. The same special case rules as for
145// float-to-int apply here.
146%def op_double_to_int():
147%  generic_funop(instr="fcvt.w.d t1, ft0, rtz", dst="w", src="d", nan_zeroed=True)
148
149// double-to-long vA, vB
150// Format 12x: B|A|8b
151// Note: Conversion of double to int64, using round-toward-zero. The same special case rules as for
152// float-to-long apply here.
153%def op_double_to_long():
154%  generic_funop(instr="fcvt.l.d t1, ft0, rtz", dst="l", src="d", nan_zeroed=True)
155
156// double-to-float vA, vB
157// Format 12x: B|A|8c
158// Note: Conversion of double to float, using round-to-nearest. This loses precision for some values.
159// Note: For ties, the IEEE 754-2008 standard defaults to "roundTiesToEven" for binary floats.
160%def op_double_to_float():
161%  generic_funop(instr="fcvt.s.d ft0, ft0, rne", dst="s", src="d")
162
163// unop boilerplate
164// instr: operand held in t1 or ft0, result written to t1 or ft0.
165// instr must not clobber t2.
166// dst: one of w (int32), l (int64), s (float), d (double)
167// src: one of w (int32), l (int64), s (float), d (double)
168// Clobbers: ft0, t0, t1, t2
169%def generic_funop(instr, dst, src, nan_zeroed=False):
170    srliw t0, xINST, 12        // t0 := B
171    srliw t2, xINST, 8         // t2 := B|A
172
173%  if src == "w":
174%    get_vreg("t1", "t0")     #  t1 := fp[B]
175%  elif src == "l":
176     GET_VREG_WIDE t1, t0     // t1 := fp[B]
177%  elif src == "s":
178%    get_vreg_float("ft0", "t0")  #  ft0 := fp[B]
179%  elif src == "d":
180     GET_VREG_DOUBLE ft0, t0  // ft0 := fp[B]
181%  else:
182%    assert false, src
183%#:
184    and t2, t2, 0xF            // t2 := A
185    FETCH_ADVANCE_INST 1       // advance xPC, load xINST
186%  if nan_zeroed:
187     // Okay to clobber T1. It is not read if nan_zeroed=True.
188     fclass.${src} t1, ft0  // fclass.s or fclass.d on the source register ft0
189     sltiu t1, t1, 0x100    // t1 := 0 if NaN, per dex spec. Skip the conversion.
190     beqz t1, 1f
191%#:
192    $instr                     // read operand (from t1|ft0), write result (to t1|ft0)
193                               // do not clobber t2!
1941:
195
196%  if dst == "w":
197%    set_vreg("t1", "t2", z0="t0")   #  fp[A] := t1
198%  elif dst == "l":
199     SET_VREG_WIDE t1, t2, z0=t0     // fp[A] := t1
200%  elif dst == "s":
201%    set_vreg_float("ft0", "t2", z0="t0")  # fp[A] := ft0
202%  elif dst == "d":
203     SET_VREG_DOUBLE ft0, t2, z0=t0  // fp[B] := ft0
204%  else:
205%    assert false, dst
206%#:
207
208   GET_INST_OPCODE t0         // t0 holds next opcode
209   GOTO_OPCODE t0             // continue to next
210
211//
212// fbinop vAA, vBB, vCC
213// Format 23x: AA|op CC|BB
214//
215
216// add-float vAA, vBB, vCC
217// Format 23x: AA|a6 CC|BB
218%def op_add_float():
219%  generic_fbinop(instr="fadd.s fa0, fa0, fa1, rne")
220
221// sub-float vAA, vBB, vCC
222// Format 23x: AA|a7 CC|BB
223%def op_sub_float():
224%  generic_fbinop(instr="fsub.s fa0, fa0, fa1, rne")
225
226// mul-float vAA, vBB, vCC
227// Format 23x: AA|a8 CC|BB
228%def op_mul_float():
229%  generic_fbinop(instr="fmul.s fa0, fa0, fa1, rne")
230
231// div-float vAA, vBB, vCC
232// Format 23x: AA|a9 CC|BB
233%def op_div_float():
234%  generic_fbinop(instr="fdiv.s fa0, fa0, fa1, rne")
235
236// rem-float vAA, vBB, vCC
237// Format 23x: AA|aa CC|BB
238// Note: Floating point remainder after division. This function is different than IEEE 754 remainder
239// and is defined as result == a - roundTowardZero(a / b) * b.
240// Note: RISC-V does not offer floating point remainder; use fmodf in libm.
241%def op_rem_float():
242%  generic_fbinop(instr="call fmodf")
243
244// add-double vAA, vBB, vCC
245// Format 23x: AA|ab CC|BB
246%def op_add_double():
247%  generic_fbinop(instr="fadd.d fa0, fa0, fa1, rne", is_double=True)
248
249// sub-double vAA, vBB, vCC
250// Format 23x: AA|ac CC|BB
251%def op_sub_double():
252%  generic_fbinop(instr="fsub.d fa0, fa0, fa1, rne", is_double=True)
253
254// mul-double vAA, vBB, vCC
255// Format 23x: AA|ad CC|BB
256%def op_mul_double():
257%  generic_fbinop(instr="fmul.d fa0, fa0, fa1, rne", is_double=True)
258
259// div-double vAA, vBB, vCC
260// Format 23x: AA|ae CC|BB
261%def op_div_double():
262%  generic_fbinop(instr="fdiv.d fa0, fa0, fa1, rne", is_double=True)
263
264// rem-double vAA, vBB, vCC
265// Format 23x: AA|af CC|BB
266// Note: Floating point remainder after division. This function is different than IEEE 754 remainder
267// and is defined as result == a - roundTowardZero(a / b) * b.
268// Note: RISC-V does not offer floating point remainder; use fmod in libm.
269%def op_rem_double():
270%  generic_fbinop(instr="call fmod", is_double=True)
271
272// fbinop boilerplate
273// instr: operands held in fa0 and fa1, result written to fa0
274// instr may be a libm call, so:
275//  - avoid caller-save state across instr; s11 is used instead.
276//  - fa0 and fa1 are used instead of ft0 and ft1.
277//
278// The is_double flag ensures vregs are read and written in 64-bit widths.
279// Clobbers: t0, t1, fa0, fa1, s11
280%def generic_fbinop(instr, is_double=False):
281   FETCH t0, count=1     // t0 := CC|BB
282   srliw s11, xINST, 8   // s11 := AA
283   srliw t1, t0, 8       // t1 := CC
284   and t0, t0, 0xFF      // t0 := BB
285%  get_vreg_float("fa1", "t1", is_double=is_double)
286                         // fa1 := fp[CC]
287%  get_vreg_float("fa0", "t0", is_double=is_double)
288                         // fa0 := fp[BB]
289   FETCH_ADVANCE_INST 2  // advance xPC, load xINST
290   $instr                // read fa0 and fa1, write result to fa0.
291                         // instr may be a function call.
292%  set_vreg_float("fa0", "s11", z0="t0", is_double=is_double)
293                         // fp[AA] := fa0
294   GET_INST_OPCODE t0    // t0 holds next opcode
295   GOTO_OPCODE t0        // continue to next
296
297//
298// fbinop/2addr vA, vB
299// Format 12x: B|A|op
300//
301
302// add-float/2addr vA, vB
303// Format 12x: B|A|c6
304%def op_add_float_2addr():
305%  generic_fbinop_2addr(instr="fadd.s fa0, fa0, fa1")
306
307// sub-float/2addr vA, vB
308// Format 12x: B|A|c7
309%def op_sub_float_2addr():
310%  generic_fbinop_2addr(instr="fsub.s fa0, fa0, fa1")
311
312// mul-float/2addr vA, vB
313// Format 12x: B|A|c8
314%def op_mul_float_2addr():
315%  generic_fbinop_2addr(instr="fmul.s fa0, fa0, fa1")
316
317// div-float/2addr vA, vB
318// Format 12x: B|A|c9
319%def op_div_float_2addr():
320%  generic_fbinop_2addr(instr="fdiv.s fa0, fa0, fa1")
321
322// rem-float/2addr vA, vB
323// Format 12x: B|A|ca
324// Note: Floating point remainder after division. This function is different than IEEE 754 remainder
325// and is defined as result == a - roundTowardZero(a / b) * b.
326// Note: RISC-V does not offer floating point remainder; use fmodf in libm.
327%def op_rem_float_2addr():
328%  generic_fbinop_2addr(instr="call fmodf")
329
330// add-double/2addr vA, vB
331// Format 12x: B|A|cb
332%def op_add_double_2addr():
333%  generic_fbinop_2addr(instr="fadd.d fa0, fa0, fa1", is_double=True)
334
335// sub-double/2addr vA, vB
336// Format 12x: B|A|cc
337%def op_sub_double_2addr():
338%  generic_fbinop_2addr(instr="fsub.d fa0, fa0, fa1", is_double=True)
339
340// mul-double/2addr vA, vB
341// Format 12x: B|A|cd
342%def op_mul_double_2addr():
343%  generic_fbinop_2addr(instr="fmul.d fa0, fa0, fa1", is_double=True)
344
345// div-double/2addr vA, vB
346// Format 12x: B|A|ce
347%def op_div_double_2addr():
348%  generic_fbinop_2addr(instr="fdiv.d fa0, fa0, fa1", is_double=True)
349
350// rem-double/2addr vA, vB
351// Format 12x: B|A|cf
352// Note: Floating point remainder after division. This function is different than IEEE 754 remainder
353// and is defined as result == a - roundTowardZero(a / b) * b.
354// Note: RISC-V does not offer floating point remainder; use fmod in libm.
355%def op_rem_double_2addr():
356%  generic_fbinop_2addr(instr="call fmod", is_double=True)
357
358// fbinop/2addr boilerplate
359// instr: operands held in fa0 and fa1, result written to fa0
360// instr may be a libm call, so:
361//  - avoid caller-save state across instr; s11 is used instead.
362//  - use fa0 and fa1 instead of ft0 and ft1.
363//
364// The is_double flag ensures vregs are read and written in 64-bit widths.
365// Clobbers: t0, t1, fa0, fa1, s11
366%def generic_fbinop_2addr(instr, is_double=False):
367   srliw t0, xINST, 8       // t0 := B|A
368   srliw t1, xINST, 12      // t1 := B
369   and t0, t0, 0xF          // t0 := A
370%  get_vreg_float("fa1", "t1", is_double=is_double)
371                             // fa1 := fp[B]
372   mv s11, t0               // s11 := A
373%  get_vreg_float("fa0", "t0", is_double=is_double)
374                             // fa0 := fp[A]
375   FETCH_ADVANCE_INST 1     // advance xPC, load xINST
376   $instr                   // read fa0 and f1, write result to fa0.
377                            // instr may be a function call.
378   GET_INST_OPCODE t1       // t1 holds next opcode
379%  set_vreg_float("fa0", "s11", z0="t0", is_double=is_double)
380                            // fp[A] := fa0
381   GOTO_OPCODE t1           // continue to next
382