From 8acdaa7eb2fe4c4858bf66764112d4180f126b07 Mon Sep 17 00:00:00 2001
From: Richard Kreckel <kreckel@ginac.de>
Date: Tue, 26 Apr 2022 00:14:39 +0200
Subject: [PATCH] Remove all #if-def'ed out code regarding
 mulusmall_loop_up/down.

With a view on d58e9198, let's accept that 'digit' can be arbitrary.
---
 src/base/digitseq/cl_DS.h            | 12 ++++++------
 src/base/digitseq/cl_asm_arm_.cc     | 27 +++------------------------
 src/integer/conv/cl_I_from_digits.cc |  1 -
 3 files changed, 9 insertions(+), 31 deletions(-)

diff --git a/src/base/digitseq/cl_DS.h b/src/base/digitseq/cl_DS.h
index a4389cc..3964e6b 100644
--- a/src/base/digitseq/cl_DS.h
+++ b/src/base/digitseq/cl_DS.h
@@ -1148,9 +1148,9 @@ inline uintD divucopy_loop_down (uintD digit, const uintD* sourceptr, uintD* des
 // Multiplikations-Einfachschleife:
 // Multipliziert eine UDS mit einem kleinen Digit und addiert ein kleines Digit.
 // mulusmall_loop_down(digit,ptr,len,newdigit)
-// multipliziert die UDS  ptr[-len..-1]  mit digit (>=2, <=36),
-// addiert dabei newdigit (>=0, <digit) zur letzten Ziffer,
-// und liefert den Carry (>=0, <digit).
+// multipliziert die UDS  ptr[-len..-1]  mit digit,
+// addiert dabei newdigit zur letzten Ziffer,
+// und liefert den Carry.
   #if HAVE_DD
   inline uintD mulusmall_loop_down (uintD digit, uintD* ptr, uintC len, uintD newdigit)
     { var uintDD carry = newdigit;
@@ -1862,9 +1862,9 @@ inline uintD divucopy_loop_down (uintD digit, const uintD* sourceptr, uintD* des
 // Multiplikations-Einfachschleife:
 // Multipliziert eine UDS mit einem kleinen Digit und addiert ein kleines Digit.
 // mulusmall_loop_up(digit,ptr,len,newdigit)
-// multipliziert die UDS  ptr[0..len-1]  mit digit (>=2, <=36),
-// addiert dabei newdigit (>=0, <digit) zur letzten Ziffer,
-// und liefert den Carry (>=0, <digit).
+// multipliziert die UDS  ptr[0..len-1]  mit digit,
+// addiert dabei newdigit zur letzten Ziffer,
+// und liefert den Carry.
   #if HAVE_DD
   inline uintD mulusmall_loop_up (uintD digit, uintD* ptr, uintC len, uintD newdigit)
     { var uintDD carry = newdigit;
diff --git a/src/base/digitseq/cl_asm_arm_.cc b/src/base/digitseq/cl_asm_arm_.cc
index d333fdb..00f9a09 100644
--- a/src/base/digitseq/cl_asm_arm_.cc
+++ b/src/base/digitseq/cl_asm_arm_.cc
@@ -1807,27 +1807,18 @@ LABEL(mulusmall_loop_down_l1)
         MOV     a1,a4                   // return carry
         LDMFD   sp!,{v1,pc}
 #else
-        STMFD   sp!,{v1-v2,lr}
+        STMFD   sp!,{v1-v4,lr}
 LABEL(mulusmall_loop_down_l1)
         LDR     ip,[a2,#-4]!
 
-//      BL      mulu32_64_vregs         // muluD(digit,*--ptr,hi=,lo=)
-// replaced by multiplication of a small x = a1 and a big y = ip :
-        MOV     v1,ip,LSR #16           // top half of y
-        BIC     ip,ip,v1,LSL #16        // bottom half of y
-        MUL     v2,a1,v1                // middle section of result
-        MUL     v1,a1,ip                // low section of result
-        MOV     ip,#0                   // high section of result
-        ADDS    v1,v1,v2,LSL #16        // bottom 32 bits of result
-        ADC     ip,ip,v2,LSR #16        // top 32 bits of result
-
+        BL      mulu32_64_vregs         // muluD(digit,*--ptr,hi=,lo=)
         ADDS    v1,v1,a4                // lo += carry
         ADC     a4,ip,#0                // if (lo<carry) { hi += 1 }; carry=hi
         STR     v1,[a2,#0]              // *ptr = lo
         SUBS    a3,a3,#1                // len--
         BNE     mulusmall_loop_down_l1  // until len==0
         MOV     a1,a4                   // return carry
-        LDMFD   sp!,{v1-v2,pc}
+        LDMFD   sp!,{v1-v4,pc}
 #endif
 
 // extern void mulu_loop_down (uintD digit, uintD* sourceptr, uintD* destptr, uintC len);
@@ -3284,19 +3275,7 @@ LABEL(mulusmall_loop_up_l1)
 LABEL(mulusmall_loop_up_l1)
         LDR     ip,[a2]
 
-#if 1
         BL      mulu32_64_vregs         // muluD(digit,*ptr,hi=,lo=)
-#else
-// this code requires that digit is small, but this condition is violated in
-// digits_to_I_baseN(const char * MSBptr, uintC len, uintD base)
-        MOV     v1,ip,LSR #16           // top half of y
-        BIC     ip,ip,v1,LSL #16        // bottom half of y
-        MUL     v2,a1,v1                // middle section of result
-        MUL     v1,a1,ip                // low section of result
-        MOV     ip,#0                   // high section of result
-        ADDS    v1,v1,v2,LSL #16        // bottom 32 bits of result
-        ADC     ip,ip,v2,LSR #16        // top 32 bits of result
-#endif
         ADDS    v1,v1,a4                // lo += carry
         ADC     a4,ip,#0                // if (lo<carry) { hi += 1 }; carry=hi
         STR     v1,[a2],#4              // *ptr++ = lo
diff --git a/src/integer/conv/cl_I_from_digits.cc b/src/integer/conv/cl_I_from_digits.cc
index 1819f5e..681c51d 100644
--- a/src/integer/conv/cl_I_from_digits.cc
+++ b/src/integer/conv/cl_I_from_digits.cc
@@ -134,7 +134,6 @@ static const cl_I digits_to_I_baseN (const char * MSBptr, uintC len, uintD base)
 			chx++;
 			len--;
 		}
-		// FIXME: mulusmall_loop_up/down are documented to require a small factor (<= 36).
 		var uintD carry = mulusmall_loop_lsp(factor,erg_LSDptr,erg_len,newdigit);
 		if (carry!=0) {
 			// need to extend NUDS:
-- 
2.49.0