diff mbox series

[v6,34/34] Add -mpure-code support to the CM0 functions.

Message ID 20211227190530.3136549-35-gnu@danielengel.com
State New
Headers show
Series libgcc: Thumb-1 Floating-Point Assembly for Cortex M0 | expand

Commit Message

Daniel Engel Dec. 27, 2021, 7:05 p.m. UTC
gcc/libgcc/ChangeLog:
2021-01-16 Daniel Engel <gnu@danielengel.com>

	Makefile.in (MPURE_CODE): New macro defines __PURE_CODE__.
	(gcc_compile): Appended MPURE_CODE.
	lib1funcs.S (FUNC_START_SECTION): Set flags for __PURE_CODE__.
	clz2.S (__clzsi2): Added -mpure-code compatible instructions.
	ctz2.S (__ctzsi2): Same.
	popcnt.S (__popcountsi2, __popcountdi2): Same.
---
 libgcc/Makefile.in            |  5 ++++-
 libgcc/config/arm/clz2.S      | 25 ++++++++++++++++++++++-
 libgcc/config/arm/ctz2.S      | 38 +++++++++++++++++++++++++++++++++--
 libgcc/config/arm/lib1funcs.S |  7 ++++++-
 libgcc/config/arm/popcnt.S    | 33 +++++++++++++++++++++++++-----
 5 files changed, 98 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/libgcc/Makefile.in b/libgcc/Makefile.in
index 32e329f7764..e6b2ce5c6d7 100644
--- a/libgcc/Makefile.in
+++ b/libgcc/Makefile.in
@@ -307,6 +307,9 @@  CRTSTUFF_CFLAGS = -O2 $(GCC_CFLAGS) $(INCLUDES) $(MULTILIB_CFLAGS) -g0 \
 # Extra flags to use when compiling crt{begin,end}.o.
 CRTSTUFF_T_CFLAGS =
 
+# Pass the -mpure-code flag into assembly for conditional compilation.
+MPURE_CODE = $(if $(findstring -mpure-code,$(CFLAGS)), -D__PURE_CODE__)
+
 MULTIDIR := $(shell $(CC) $(CFLAGS) -print-multi-directory)
 MULTIOSDIR := $(shell $(CC) $(CFLAGS) -print-multi-os-directory)
 
@@ -316,7 +319,7 @@  inst_slibdir = $(slibdir)$(MULTIOSSUBDIR)
 
 gcc_compile_bare = $(CC) $(INTERNAL_CFLAGS) $(CFLAGS-$(<F))
 compile_deps = -MT $@ -MD -MP -MF $(basename $@).dep
-gcc_compile = $(gcc_compile_bare) -o $@ $(compile_deps)
+gcc_compile = $(gcc_compile_bare) -o $@ $(compile_deps) $(MPURE_CODE)
 gcc_s_compile = $(gcc_compile) -DSHARED
 
 objects = $(filter %$(objext),$^)
diff --git a/libgcc/config/arm/clz2.S b/libgcc/config/arm/clz2.S
index a2de45ff651..97a44f5d187 100644
--- a/libgcc/config/arm/clz2.S
+++ b/libgcc/config/arm/clz2.S
@@ -214,17 +214,40 @@  FUNC_ENTRY clzsi2
      IT(sub,ne) r2,     #4
 
     LLSYM(__clz2):
+  #if defined(__PURE_CODE__) && __PURE_CODE__
+        // Without access to table data, continue unrolling the loop.
+        lsrs    r1,     r0,     #2
+
+      #ifdef __HAVE_FEATURE_IT
+        do_it   ne,t
+      #else
+        beq     LLSYM(__clz1)
+      #endif
+
+        // Out of 4 bits, the first '1' is somewhere in the highest 2,
+        //  so the lower 2 bits are no longer interesting.
+     IT(mov,ne) r0,     r1
+     IT(sub,ne) r2,     #2
+
+    LLSYM(__clz1):
+        // Convert remainder {0,1,2,3} to {0,1,2,2}.
+        lsrs    r1,     r0,     #1
+        bics    r0,     r1
+
+  #else /* !__PURE_CODE__ */
         // Load the remainder by index
         adr     r1,     LLSYM(__clz_remainder)
         ldrb    r0,     [r1, r0]
 
+  #endif /* !__PURE_CODE__ */
   #endif /* !__OPTIMIZE_SIZE__ */
 
         // Account for the remainder.
         subs    r0,     r2,     r0
         RET
 
-  #if !defined(__OPTIMIZE_SIZE__) || !__OPTIMIZE_SIZE__
+  #if !(defined(__OPTIMIZE_SIZE__) && __OPTIMIZE_SIZE__) && \
+      !(defined(__PURE_CODE__) && __PURE_CODE__)
         .align 2
     LLSYM(__clz_remainder):
         .byte 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4
diff --git a/libgcc/config/arm/ctz2.S b/libgcc/config/arm/ctz2.S
index b9528a061a2..6a49d64f3a6 100644
--- a/libgcc/config/arm/ctz2.S
+++ b/libgcc/config/arm/ctz2.S
@@ -209,11 +209,44 @@  FUNC_ENTRY ctzsi2
      IT(sub,ne) r2,     #4
 
     LLSYM(__ctz2):
+  #if defined(__PURE_CODE__) && __PURE_CODE__
+        // Without access to table data, continue unrolling the loop.
+        lsls    r1,     r0,     #2
+
+      #ifdef __HAVE_FEATURE_IT
+        do_it   ne, t
+      #else
+        beq     LLSYM(__ctz1)
+      #endif
+
+        // Out of 4 bits, the first '1' is somewhere in the lowest 2,
+        //  so the higher 2 bits are no longer interesting.
+     IT(mov,ne) r0,     r1
+     IT(sub,ne) r2,     #2
+
+    LLSYM(__ctz1):
+        // Convert remainder {0,1,2,3} in $r0[31:30] to {0,2,1,2}.
+        lsrs    r0,     #31
+
+      #ifdef __HAVE_FEATURE_IT
+        do_it   cs, t
+      #else
+        bcc     LLSYM(__ctz_zero)
+      #endif
+
+        // If bit[30] of the remainder is set, neither of these bits count
+        //  towards the result.  Bit[31] must be cleared.
+        // Otherwise, bit[31] becomes the final remainder.
+     IT(sub,cs) r2,     #2
+     IT(eor,cs) r0,     r0
+
+  #else /* !__PURE_CODE__ */
         // Look up the remainder by index.
         lsrs    r0,     #28
         adr     r3,     LLSYM(__ctz_remainder)
         ldrb    r0,     [r3, r0]
 
+  #endif /* !__PURE_CODE__ */
   #endif /* !__OPTIMIZE_SIZE__ */
 
     LLSYM(__ctz_zero):
@@ -221,8 +254,9 @@  FUNC_ENTRY ctzsi2
         subs    r0,     r2,     r0
         RET
 
-  #if (!defined(__ARM_FEATURE_CLZ) || !__ARM_FEATURE_CLZ) && \
-      (!defined(__OPTIMIZE_SIZE__) || !__OPTIMIZE_SIZE__)
+  #if !(defined(__ARM_FEATURE_CLZ) && __ARM_FEATURE_CLZ) && \
+      !(defined(__OPTIMIZE_SIZE__) && __OPTIMIZE_SIZE__) && \
+      !(defined(__PURE_CODE__) && __PURE_CODE__)
         .align 2
     LLSYM(__ctz_remainder):
         .byte 0,4,3,4,2,4,3,4,1,4,3,4,2,4,3,4
diff --git a/libgcc/config/arm/lib1funcs.S b/libgcc/config/arm/lib1funcs.S
index 5148957144b..59b2370e160 100644
--- a/libgcc/config/arm/lib1funcs.S
+++ b/libgcc/config/arm/lib1funcs.S
@@ -454,7 +454,12 @@  SYM (\name):
    Use the *_START_SECTION macros for declarations that the linker should
     place in a non-defailt section (e.g. ".rodata", ".text.subsection"). */
 .macro FUNC_START_SECTION name section
-	.section \section,"x"
+#ifdef __PURE_CODE__
+	/* SHF_ARM_PURECODE | SHF_ALLOC | SHF_EXECINSTR */
+	.section \section,"0x20000006",%progbits
+#else
+	.section \section,"ax",%progbits
+#endif
 	.align 0
 	FUNC_ENTRY \name
 .endm
diff --git a/libgcc/config/arm/popcnt.S b/libgcc/config/arm/popcnt.S
index 51b1ed745ee..d6f65403b5d 100644
--- a/libgcc/config/arm/popcnt.S
+++ b/libgcc/config/arm/popcnt.S
@@ -23,6 +23,29 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 
+#if defined(L_popcountdi2) || defined(L_popcountsi2)
+
+.macro ldmask reg, temp, value
+    #if defined(__PURE_CODE__) && (__PURE_CODE__)
+      #ifdef NOT_ISA_TARGET_32BIT
+        movs    \reg,   \value
+        lsls    \temp,  \reg,   #8
+        orrs    \reg,   \temp
+        lsls    \temp,  \reg,   #16
+        orrs    \reg,   \temp
+      #else
+        // Assumption: __PURE_CODE__ only support M-profile.
+        movw    \reg    ((\value) * 0x101)
+        movt    \reg    ((\value) * 0x101)
+      #endif
+    #else
+        ldr     \reg,   =((\value) * 0x1010101)
+    #endif
+.endm
+
+#endif
+
+
 #ifdef L_popcountdi2
 
 // int __popcountdi2(int)
@@ -49,7 +72,7 @@  FUNC_START_SECTION popcountdi2 .text.sorted.libgcc.popcountdi2
 
   #else /* !__OPTIMIZE_SIZE__ */
         // Load the one-bit alternating mask.
-        ldr     r3,     =0x55555555
+        ldmask  r3,     r2,     0x55
 
         // Reduce the second word.
         lsrs    r2,     r1,     #1
@@ -62,7 +85,7 @@  FUNC_START_SECTION popcountdi2 .text.sorted.libgcc.popcountdi2
         subs    r0,     r2
 
         // Load the two-bit alternating mask.
-        ldr     r3,     =0x33333333
+        ldmask  r3,     r2,     0x33
 
         // Reduce the second word.
         lsrs    r2,     r1,     #2
@@ -140,7 +163,7 @@  FUNC_ENTRY popcountsi2
   #else /* !__OPTIMIZE_SIZE__ */
 
         // Load the one-bit alternating mask.
-        ldr     r3,     =0x55555555
+        ldmask  r3,     r2,     0x55
 
         // Reduce the word.
         lsrs    r1,     r0,     #1
@@ -148,7 +171,7 @@  FUNC_ENTRY popcountsi2
         subs    r0,     r1
 
         // Load the two-bit alternating mask.
-        ldr     r3,     =0x33333333
+        ldmask  r3,     r2,     0x33
 
         // Reduce the word.
         lsrs    r1,     r0,     #2
@@ -158,7 +181,7 @@  FUNC_ENTRY popcountsi2
         adds    r0,     r1
 
         // Load the four-bit alternating mask.
-        ldr     r3,     =0x0F0F0F0F
+        ldmask  r3,     r2,     0x0F
 
         // Reduce the word.
         lsrs    r1,     r0,     #4