From: Taylor R Campbell <campbell@mumble.net>
Date: Fri, 18 Jan 2019 06:23:00 +0000 (+0000)
Subject: Fix passage of dynamic-link.  Only machine register, not regblock.
X-Git-Tag: mit-scheme-pucked-10.1.20~11^2~66^2~71
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=56fde00c4a7b70eccb87298c4d33d3616c05fc05;p=mit-scheme.git

Fix passage of dynamic-link.  Only machine register, not regblock.
---

diff --git a/src/compiler/machines/aarch64/lapgen.scm b/src/compiler/machines/aarch64/lapgen.scm
index a016fc79e..82b330f9c 100644
--- a/src/compiler/machines/aarch64/lapgen.scm
+++ b/src/compiler/machines/aarch64/lapgen.scm
@@ -465,7 +465,6 @@ USA.
 
 (define reg:memtop (regblock-ea register-block/memtop-offset))
 (define reg:environment (regblock-ea register-block/environment-offset))
-(define reg:dynamic-link (regblock-ea register-block/dynamic-link-offset))
 (define reg:lexpr-primitive-arity
   (regblock-ea register-block/lexpr-primitive-arity-offset))
 (define reg:stack-guard (regblock-ea register-block/stack-guard-offset))
diff --git a/src/compiler/machines/aarch64/machine.scm b/src/compiler/machines/aarch64/machine.scm
index 22e5df9b4..47dd5c8c5 100644
--- a/src/compiler/machines/aarch64/machine.scm
+++ b/src/compiler/machines/aarch64/machine.scm
@@ -300,7 +300,6 @@ USA.
 (define-integrable register-block/int-mask-offset 1)
 (define-integrable register-block/value-offset 2)
 (define-integrable register-block/environment-offset 3)
-(define-integrable register-block/dynamic-link-offset 4) ; compiler temp
 (define-integrable register-block/lexpr-primitive-arity-offset 7)
 (define-integrable register-block/stack-guard-offset 11)
 (define-integrable register-block/int-code-offset 12)
diff --git a/src/compiler/machines/aarch64/rules3.scm b/src/compiler/machines/aarch64/rules3.scm
index 8afe6b979..ac258e334 100644
--- a/src/compiler/machines/aarch64/rules3.scm
+++ b/src/compiler/machines/aarch64/rules3.scm
@@ -452,8 +452,7 @@ USA.
    code-word
    label
    (lambda ()
-     ;; Save the dynamic link to an interpreter register, and then ask
-     ;; for help from the microcode.
+     ;; Pass the dynamic link as utility argument 2.
      ;;
      ;; XXX The goal of sharing here is to reduce code size; it would
      ;; be nice if we could ask the assembler to not share if we're so
@@ -468,7 +467,8 @@ USA.
       (LAP (B (@PCR ,subroutine ,regnum:scratch-0))))
     (lambda (subroutine)
       (LAP (LABEL ,subroutine)
-           (STR X ,regnum:dynamic-link ,reg:dynamic-link)
+           ,@(register->register-transfer regnum:dynamic-link
+                                          regnum:utility-arg2)
            ,@(invoke-interface code:compiler-interrupt-dlink)))))
 
 (define-rule statement
diff --git a/src/microcode/cmpauxmd/aarch64.m4 b/src/microcode/cmpauxmd/aarch64.m4
index 2c7dea567..d7fc694ec 100644
--- a/src/microcode/cmpauxmd/aarch64.m4
+++ b/src/microcode/cmpauxmd/aarch64.m4
@@ -53,6 +53,7 @@ define(ADRL,`
 
 	// Scheme machine registers.  Must agree with
 	// aarch64/machine.scm, aarch64/lapgen.scm.
+	VAL		.req x0
 	UARG1		.req x1
 	UARG2		.req x2
 	UARG3		.req x3
@@ -69,7 +70,6 @@ define(ADRL,`
 	// Interpreter register block offsets.  Must agree with
 	// const.h.
 	.equiv	REGBLOCK_VAL,		2
-	.equiv	REGBLOCK_DYNLINK,	4	// REGBLOCK_CC_TEMP
 
 ///////////////////////////////////////////////////////////////////////////////
 // Entering Scheme from C
@@ -170,14 +170,15 @@ END(interface_to_C)
 	//	Steps:
 	//
 	//	1. Save value, Free, and stack_pointer.
-	//	   => No need to save REGS because it's callee-saves.
+	//	   => No need to save REGS or HOOKS because callee-saves.
+	//	   => If DYNLINK is active, will be utility argument 2.
 	//	2. Allocate a struct on the stack for return values in x0.
 	//	3. Call the function in utility_table.
 	//	4. Go to wherever the microcode directed us.
 	//
 GLOBAL(scheme_to_interface)
 	// Save value, Free, and stack_pointer.
-	str	x0, [REGS,#REGBLOCK_VAL]
+	str	VAL, [REGS,#(REGBLOCK_VAL*8)]
 	ADRL(ip0,Free)			// address of Free pointer
 	str	FREE, [ip0]		// store current Free pointer
 	ADRL(ip0,stack_pointer)		// address of stack pointer
@@ -253,6 +254,8 @@ END(interface_to_scheme_return)
 	//	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.
+	//	  (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
@@ -264,8 +267,10 @@ END(interface_to_scheme_return)
 	//	interface_to_scheme_return.
 	//
 LOCAL(interface_to_scheme_setup)
-	// Restore value, Free, and stack_pointer.
-	ldr	x0, [REGS,#REGBLOCK_VAL]
+	// Restore value if it was in use, dynamic link if it was in
+	// use, Free, and stack_pointer.
+	ldr	VAL, [REGS,#(REGBLOCK_VAL*8)]
+	mov	DYNLINK, VAL
 	ADRL(FREE,Free)			// address of Free pointer
 	ldr	FREE, [FREE]		// load current Free pointer
 	ADRL(SSP,stack_pointer)		// address of stack pointer
@@ -344,8 +349,11 @@ $1:
 	// UTILITY_HOOK(name, number)
 	//
 	//	Hook that jumps to the utility with the specified
-	//	number.  Reduces caller code size.  The number must
-	//	match utility_table in cmpint.c.
+	//	number.  Does not reduce caller code size, so use this
+	//	only as an interim for cases where we are likely to
+	//	add some extra logic here soon that would help to
+	//	reduce caller code size.  The number must match
+	//	utility_table in cmpint.c.
 	//
 define(UTILITY_HOOK, `
 $1: