Make interface_to_scheme match reality, not sensibility.

Should change cmpint.c so we pass a separate dispatch routine in for
entries and continuations, but that requires changing all the
cmpauxen at once.

diff --git a/src/microcode/cmpauxmd/aarch64.m4 b/src/microcode/cmpauxmd/aarch64.m4
index d7fc694ec0304dd0b45628f642c2e8599bf72e8c..19da66a061a659f376825d86f269934a93739ae4 100644 (file)
--- a/src/microcode/cmpauxmd/aarch64.m4
+++ b/src/microcode/cmpauxmd/aarch64.m4
@@ -213,60 +213,23 @@ END(scheme_to_interface)
 
        // void interface_to_scheme (insn_t * entry@x1, insn_t * pc@x17)
        //
-       //      When a utility wants to return control to Scheme at an
-       //      entry, it directs scheme_to_interface_return to jump
-       //      here, with x0 set to the entry address (such as a
-       //      pointer to a compiled closure) and x1 set to the entry
-       //      PC (the actual instructions to execute).
-       //
-GLOBAL(interface_to_scheme)
-       // Set up the transition.
-       bl      SYMBOL(interface_to_scheme_setup)
-
-       // Jump to Scheme.
-       br      APPLICAND_PC
-END(interface_to_scheme)
-
-       // void interface_to_scheme_return (insn_t * entry@x1, insn_t * pc@x17)
-       //
-       //      When a utility wants to return to a Scheme return
-       //      address, it directs scheme_to_interface_return to
-       //      return here.  We then RET to the specified pc.  This
-       //      ensures that if the utility was called via
-       //      branch-and-link, we will use RET to return so that
-       //      calls and returns are paired, which enables the CPU's
-       //      return address branch target predictor to work.
-       //
-GLOBAL(interface_to_scheme_return)
-       // Set up the transition.
-       bl      SYMBOL(interface_to_scheme_setup)
-
-       // Return to Scheme.
-       mov     lr, APPLICAND_PC
-       ret
-END(interface_to_scheme_return)
-
-       // insn_t *
-       // interface_to_scheme_setup (insn_t * entry@x1, insn_t * pc@x17)
-       //
        //      Set up a transition to compiled Scheme code after a
        //      utility return, whether we are jumping to a Scheme
        //      entry or returning to a Scheme return address.
        //
-       //      - Sets x0 to be the preserved return value, if any.
-       //      - Sets x21 to be the preserved dynamic link, if any.
+       //      - Set x0 to be the preserved return value, if any.
+       //      - Set x21 to be the preserved dynamic link, if any.
        //        (Both were in REGBLOCK_VAL.)
-       //      - Sets up x20 (FREE) and x28 (Scheme SP).
-       //      - Preserves x1 (APPLICAND) and x17 (APPLICAND_PC).
-       //      - Does not touch REGS (x19) or HOOKS (x23) because
+       //      - Set up x20 (FREE) and x28 (Scheme SP).
+       //      - Preserve x1 (APPLICAND).
+       //      - Preserve not touch REGS (x19) or HOOKS (x23) because
        //        those are callee-saves and unmodified by C.
-       //      - XXX Should we restore DYNLINK (x21)?
        //
-       //      This is NOT a normal ARM ABI subroutine.  Meant to be
-       //      used only from interface_to_scheme or
-       //      interface_to_scheme_return.
+       //      Finally, jump to pc, x17, which is either the first PC
+       //      of a compiled entry, or interface_to_scheme_return if
+       //      we are returning to a Scheme continuation.
        //
-LOCAL(interface_to_scheme_setup)
+GLOBAL(interface_to_scheme)
        // Restore value if it was in use, dynamic link if it was in
        // use, Free, and stack_pointer.
        ldr     VAL, [REGS,#(REGBLOCK_VAL*8)]
@@ -276,9 +239,18 @@ LOCAL(interface_to_scheme_setup)
        ADRL(SSP,stack_pointer)         // address of stack pointer
        ldr     SSP, [SSP]              // load current stack pointer
 
-       // Done setting up.  Return to caller.
+       // Jump to Scheme, or to scheme_to_interface.
+       br      APPLICAND_PC
+END(interface_to_scheme)
+
+       // void interface_to_scheme_return (insn_t * entry@x1)
+       //
+       //      Issue a RET to entry, x1.
+       //
+GLOBAL(interface_to_scheme_return)
+       mov     lr, APPLICAND
        ret
-END(interface_to_scheme_setup)
+END(interface_to_scheme_return)
 \f
 ///////////////////////////////////////////////////////////////////////////////
 // Scheme unknown procedure application setup