Add expm1/ln1p math builtins (VAMS-2023)

integration_tests/VAMS2023_MATH/vams2023_math.va

@@ -0,0 +1,38 @@
+`include "constants.vams"
+`include "disciplines.vams"
+
+// Exercises the VAMS-2023 expm1()/ln1p() builtins through the whole pipeline
+// (HIR -> MIR -> autodiff -> LLVM/OSDI), including their derivatives.
+//
+// expm1 is the natural spelling for a diode current: the usual
+// is*(exp(vd/(n*vt)) - 1) cancels to zero once |vd| << n*vt, which is exactly
+// what expm1 avoids.
+module vams2023_math(A, C);
+    inout A, C;
+    electrical A, C;
+
+    branch (A, C) br_ac;
+
+    (*desc = "Saturation current", units = "A"*) parameter real is = 1e-14 from [0:inf];
+    (*desc = "Emission coefficient"*) parameter real n = 1.0 from (0:inf);
+    (*desc = "Leakage conductance", units = "S"*) parameter real gleak = 1e-12 from [0:inf];
+
+    real vt, vd, id, vleak;
+
+    (*desc = "diode admittance", units = "S"*) real gd;
+
+    analog begin
+        vt = `P_K * $temperature / `P_Q;
+        vd = V(br_ac);
+
+        id = is * expm1(vd / (n * vt));
+
+        // Independent argument so this is not simplified into the expm1 above,
+        // which keeps ln1p and its derivative in the generated code.
+        vleak = vt * ln1p(vd / vt);
+
+        I(br_ac) <+ id + gleak * vleak;
+
+        gd = ddx(id, V(A));
+    end
+endmodule

openvaf/hir_def/src/builtin.rs

@@ -24,105 +24,107 @@ pub enum BuiltIn {
     cos = 9u8,
     cosh = 10u8,
     exp = 11u8,
-    floor = 12u8,
-    flow = 13u8,
-    potential = 14u8,
-    hypot = 15u8,
-    ln = 16u8,
-    log = 17u8,
-    max = 18u8,
-    min = 19u8,
-    pow = 20u8,
-    sin = 21u8,
-    sinh = 22u8,
-    sqrt = 23u8,
-    tan = 24u8,
-    tanh = 25u8,
-    display = 26u8,
-    strobe = 27u8,
-    write = 28u8,
-    monitor = 29u8,
-    debug = 30u8,
-    fclose = 31u8,
-    fopen = 32u8,
-    fdisplay = 33u8,
-    fwrite = 34u8,
-    fstrobe = 35u8,
-    fmonitor = 36u8,
-    fgets = 37u8,
-    fscanf = 38u8,
-    swrite = 39u8,
-    sformat = 40u8,
-    sscanf = 41u8,
-    rewind = 42u8,
-    fseek = 43u8,
-    ftell = 44u8,
-    fflush = 45u8,
-    ferror = 46u8,
-    feof = 47u8,
-    fdebug = 48u8,
-    finish = 49u8,
-    stop = 50u8,
-    fatal = 51u8,
-    warning = 52u8,
-    error = 53u8,
-    info = 54u8,
-    abstime = 55u8,
-    dist_chi_square = 56u8,
-    dist_exponential = 57u8,
-    dist_poisson = 58u8,
-    dist_uniform = 59u8,
-    dist_erlang = 60u8,
-    dist_normal = 61u8,
-    dist_t = 62u8,
-    random = 63u8,
-    arandom = 64u8,
-    rdist_chi_square = 65u8,
-    rdist_exponential = 66u8,
-    rdist_poisson = 67u8,
-    rdist_uniform = 68u8,
-    rdist_erlang = 69u8,
-    rdist_normal = 70u8,
-    rdist_t = 71u8,
-    clog2 = 72u8,
-    log10 = 73u8,
-    temperature = 74u8,
-    vt = 75u8,
-    simparam = 76u8,
-    simparam_str = 77u8,
-    simprobe = 78u8,
-    discontinuity = 79u8,
-    param_given = 80u8,
-    port_connected = 81u8,
-    analog_node_alias = 82u8,
-    analog_port_alias = 83u8,
-    test_plusargs = 84u8,
-    value_plusargs = 85u8,
-    bound_step = 86u8,
-    analysis = 87u8,
-    ac_stim = 88u8,
-    noise_table = 89u8,
-    noise_table_log = 90u8,
-    white_noise = 91u8,
-    flicker_noise = 92u8,
-    limit = 93u8,
-    absdelay = 94u8,
-    ddt = 95u8,
-    idt = 96u8,
-    idtmod = 97u8,
-    ddx = 98u8,
-    zi_nd = 99u8,
-    zi_np = 100u8,
-    zi_zd = 101u8,
-    zi_zp = 102u8,
-    laplace_nd = 103u8,
-    laplace_np = 104u8,
-    laplace_zd = 105u8,
-    laplace_zp = 106u8,
-    limexp = 107u8,
-    last_crossing = 108u8,
-    slew = 109u8,
-    transition = 110u8,
+    expm1 = 12u8,
+    floor = 13u8,
+    flow = 14u8,
+    potential = 15u8,
+    hypot = 16u8,
+    ln = 17u8,
+    ln1p = 18u8,
+    log = 19u8,
+    max = 20u8,
+    min = 21u8,
+    pow = 22u8,
+    sin = 23u8,
+    sinh = 24u8,
+    sqrt = 25u8,
+    tan = 26u8,
+    tanh = 27u8,
+    display = 28u8,
+    strobe = 29u8,
+    write = 30u8,
+    monitor = 31u8,
+    debug = 32u8,
+    fclose = 33u8,
+    fopen = 34u8,
+    fdisplay = 35u8,
+    fwrite = 36u8,
+    fstrobe = 37u8,
+    fmonitor = 38u8,
+    fgets = 39u8,
+    fscanf = 40u8,
+    swrite = 41u8,
+    sformat = 42u8,
+    sscanf = 43u8,
+    rewind = 44u8,
+    fseek = 45u8,
+    ftell = 46u8,
+    fflush = 47u8,
+    ferror = 48u8,
+    feof = 49u8,
+    fdebug = 50u8,
+    finish = 51u8,
+    stop = 52u8,
+    fatal = 53u8,
+    warning = 54u8,
+    error = 55u8,
+    info = 56u8,
+    abstime = 57u8,
+    dist_chi_square = 58u8,
+    dist_exponential = 59u8,
+    dist_poisson = 60u8,
+    dist_uniform = 61u8,
+    dist_erlang = 62u8,
+    dist_normal = 63u8,
+    dist_t = 64u8,
+    random = 65u8,
+    arandom = 66u8,
+    rdist_chi_square = 67u8,
+    rdist_exponential = 68u8,
+    rdist_poisson = 69u8,
+    rdist_uniform = 70u8,
+    rdist_erlang = 71u8,
+    rdist_normal = 72u8,
+    rdist_t = 73u8,
+    clog2 = 74u8,
+    log10 = 75u8,
+    temperature = 76u8,
+    vt = 77u8,
+    simparam = 78u8,
+    simparam_str = 79u8,
+    simprobe = 80u8,
+    discontinuity = 81u8,
+    param_given = 82u8,
+    port_connected = 83u8,
+    analog_node_alias = 84u8,
+    analog_port_alias = 85u8,
+    test_plusargs = 86u8,
+    value_plusargs = 87u8,
+    bound_step = 88u8,
+    analysis = 89u8,
+    ac_stim = 90u8,
+    noise_table = 91u8,
+    noise_table_log = 92u8,
+    white_noise = 93u8,
+    flicker_noise = 94u8,
+    limit = 95u8,
+    absdelay = 96u8,
+    ddt = 97u8,
+    idt = 98u8,
+    idtmod = 99u8,
+    ddx = 100u8,
+    zi_nd = 101u8,
+    zi_np = 102u8,
+    zi_zd = 103u8,
+    zi_zp = 104u8,
+    laplace_nd = 105u8,
+    laplace_np = 106u8,
+    laplace_zd = 107u8,
+    laplace_zp = 108u8,
+    limexp = 109u8,
+    last_crossing = 110u8,
+    slew = 111u8,
+    transition = 112u8,
 }
 #[derive(Eq, PartialEq, Copy, Clone, Hash, Debug)]
 #[allow(nonstandard_style, unreachable_pub)]
@@ -251,11 +253,13 @@ pub fn insert_builtin_scope(dst: &mut IndexMap<Name, ScopeDefItem, BuildHasherDe
     dst.insert(kw::cos, BuiltIn::cos.into());
     dst.insert(kw::cosh, BuiltIn::cosh.into());
     dst.insert(kw::exp, BuiltIn::exp.into());
+    dst.insert(kw::expm1, BuiltIn::expm1.into());
     dst.insert(kw::floor, BuiltIn::floor.into());
     dst.insert(kw::flow, BuiltIn::flow.into());
     dst.insert(kw::potential, BuiltIn::potential.into());
     dst.insert(kw::hypot, BuiltIn::hypot.into());
     dst.insert(kw::ln, BuiltIn::ln.into());
+    dst.insert(kw::ln1p, BuiltIn::ln1p.into());
     dst.insert(kw::log, BuiltIn::log.into());
     dst.insert(kw::max, BuiltIn::max.into());
     dst.insert(kw::min, BuiltIn::min.into());
@@ -313,8 +317,10 @@ pub fn insert_builtin_scope(dst: &mut IndexMap<Name, ScopeDefItem, BuildHasherDe
     dst.insert(sysfun::rdist_t, BuiltIn::rdist_t.into());
     dst.insert(sysfun::clog2, BuiltIn::clog2.into());
     dst.insert(sysfun::ln, BuiltIn::ln.into());
+    dst.insert(sysfun::ln1p, BuiltIn::ln1p.into());
     dst.insert(sysfun::log10, BuiltIn::log10.into());
     dst.insert(sysfun::exp, BuiltIn::exp.into());
+    dst.insert(sysfun::expm1, BuiltIn::expm1.into());
     dst.insert(sysfun::sqrt, BuiltIn::sqrt.into());
     dst.insert(sysfun::pow, BuiltIn::pow.into());
     dst.insert(sysfun::floor, BuiltIn::floor.into());

openvaf/hir_lower/src/expr.rs

@@ -361,6 +361,10 @@ impl BodyLoweringCtx<'_, '_, '_> {
                 let arg0 = self.lower_expr(args[0]);
                 self.ctx.ins().exp(arg0)
             }
+            BuiltIn::expm1 => {
+                let arg0 = self.lower_expr(args[0]);
+                self.ctx.ins().expm1(arg0)
+            }
 
             BuiltIn::limexp => {
                 let arg0 = self.lower_expr(args[0]);
@@ -393,6 +397,10 @@ impl BodyLoweringCtx<'_, '_, '_> {
                 let arg0 = self.lower_expr(args[0]);
                 self.ctx.ins().ln(arg0)
             }
+            BuiltIn::ln1p => {
+                let arg0 = self.lower_expr(args[0]);
+                self.ctx.ins().ln1p(arg0)
+            }
             BuiltIn::sin => {
                 let arg0 = self.lower_expr(args[0]);
                 self.ctx.ins().sin(arg0)

openvaf/hir_ty/src/builtin.rs

@@ -428,8 +428,10 @@ copied_builtins! {
     COS = REAL_MATH_1
     COSH = REAL_MATH_1
     EXP = REAL_MATH_1
+    EXPM1 = REAL_MATH_1
     FLOOR = REAL_MATH_1
     LN = REAL_MATH_1
+    LN1P = REAL_MATH_1
     LOG = REAL_MATH_1
     CLOG2 = INT_MATH_2
     LOG10 = REAL_MATH_1

openvaf/hir_ty/src/builtin/generated.rs

@@ -4,7 +4,7 @@ use hir_def::BuiltIn;
 
 use crate::builtin::*;
 
-const BUILTIN_INFO: [BuiltinInfo; 111usize] = [
+const BUILTIN_INFO: [BuiltinInfo; 113usize] = [
     ABS,
     ACOS,
     ACOSH,
@@ -17,11 +17,13 @@ const BUILTIN_INFO: [BuiltinInfo; 111usize] = [
     COS,
     COSH,
     EXP,
+    EXPM1,
     FLOOR,
     FLOW,
     POTENTIAL,
     HYPOT,
     LN,
+    LN1P,
     LOG,
     MAX,
     MIN,

openvaf/mir/src/builder/generated.rs

@@ -142,10 +142,18 @@ pub trait InstBuilder<'f>: InstBuilderBase<'f> {
         let (inst, dfg) = self.unary(Opcode::Exp, arg0);
         dfg.first_result(inst)
     }
+    fn expm1(self, arg0: Value) -> Value {
+        let (inst, dfg) = self.unary(Opcode::Expm1, arg0);
+        dfg.first_result(inst)
+    }
     fn ln(self, arg0: Value) -> Value {
         let (inst, dfg) = self.unary(Opcode::Ln, arg0);
         dfg.first_result(inst)
     }
+    fn ln1p(self, arg0: Value) -> Value {
+        let (inst, dfg) = self.unary(Opcode::Ln1p, arg0);
+        dfg.first_result(inst)
+    }
     fn log(self, arg0: Value) -> Value {
         let (inst, dfg) = self.unary(Opcode::Log, arg0);
         dfg.first_result(inst)