From 348a9048b7bed27335301f5b8d3398baceb5f84e Mon Sep 17 00:00:00 2001 From: Colin Leroy-Mira Date: Tue, 9 Jan 2024 21:28:37 +0100 Subject: [PATCH] Convert _time_t_to_tm to asm 46 bytes size gain, -8% cycles on the unit tests --- libsrc/common/_time_t_to_tm.c | 64 ----------------- libsrc/common/_time_t_to_tm.s | 129 ++++++++++++++++++++++++++++++++++ libsrc/common/mktime.c | 9 ++- 3 files changed, 135 insertions(+), 67 deletions(-) delete mode 100644 libsrc/common/_time_t_to_tm.c create mode 100644 libsrc/common/_time_t_to_tm.s diff --git a/libsrc/common/_time_t_to_tm.c b/libsrc/common/_time_t_to_tm.c deleted file mode 100644 index 684cff752..000000000 --- a/libsrc/common/_time_t_to_tm.c +++ /dev/null @@ -1,64 +0,0 @@ -/*****************************************************************************/ -/* */ -/* gmtime.c */ -/* */ -/* Convert calendar time into broken down time in UTC */ -/* */ -/* */ -/* */ -/* (C) 2002 Ullrich von Bassewitz */ -/* Wacholderweg 14 */ -/* D-70597 Stuttgart */ -/* EMail: uz@musoftware.de */ -/* */ -/* */ -/* This software is provided 'as-is', without any expressed or implied */ -/* warranty. In no event will the authors be held liable for any damages */ -/* arising from the use of this software. */ -/* */ -/* Permission is granted to anyone to use this software for any purpose, */ -/* including commercial applications, and to alter it and redistribute it */ -/* freely, subject to the following restrictions: */ -/* */ -/* 1. The origin of this software must not be misrepresented; you must not */ -/* claim that you wrote the original software. If you use this software */ -/* in a product, an acknowledgment in the product documentation would be */ -/* appreciated but is not required. */ -/* 2. Altered source versions must be plainly marked as such, and must not */ -/* be misrepresented as being the original software. */ -/* 3. This notice may not be removed or altered from any source */ -/* distribution. */ -/* */ -/*****************************************************************************/ - - - -#include - - - -/*****************************************************************************/ -/* Code */ -/*****************************************************************************/ - - -struct tm* __fastcall__ _time_t_to_tm (const time_t t) -{ - static struct tm timebuf; - /* Since our ints are just 16 bits, split the given time into seconds, - ** hours and days. Each of the values will fit in a 16 bit variable. - ** The mktime routine will then do the rest. - */ - timebuf.tm_sec = t % 3600; - timebuf.tm_min = 0; - timebuf.tm_hour = (t / 3600) % 24; - timebuf.tm_mday = (t / (3600UL * 24UL)) + 1; - timebuf.tm_mon = 0; - timebuf.tm_year = 70; /* Base value is 1/1/1970 */ - - /* Call mktime to do the final conversion */ - mktime (&timebuf); - - /* Return the result */ - return &timebuf; -} diff --git a/libsrc/common/_time_t_to_tm.s b/libsrc/common/_time_t_to_tm.s new file mode 100644 index 000000000..ffabf15fc --- /dev/null +++ b/libsrc/common/_time_t_to_tm.s @@ -0,0 +1,129 @@ +; +; Colin Leroy-Mira, 2024 +; +; struct tm* __fastcall__ _time_t_to_tm (const time_t t) +; +; Helper to gmtime and localtime. Breaks down a number of +; seconds since Jan 1, 1970 into days, hours and seconds, +; so that each of them fits in 16 bits; passes the +; result to _mktime which fixes all values in the struct, +; and returns a pointer to the struct to callers. +; + + .export __time_t_to_tm + .import udiv32, _mktime + .importzp sreg, tmp3, ptr1, ptr2, ptr3, ptr4 + + .include "time.inc" + + .macpack cpu + +__time_t_to_tm: + ; Divide number of seconds since epoch, in ptr1:sreg, + ; by 86400 to get the number of days since epoch, and + ; the number of seconds today in the remainder. + + ; Load t as dividend (sreg is already set by the caller) + sta ptr1 + stx ptr1+1 + + ; Load 86400 as divisor + lda #$80 + sta ptr3 + lda #$51 + sta ptr3+1 + lda #$01 + sta ptr4 + lda #$00 + sta ptr4+1 + + ; Clear TM buf while we have zero in A + ldx #.sizeof(tm)-1 +: sta TM,x + dex + bne :- + + ; Divide t/86400 + jsr udiv32 + + ; Store the quotient (the number of full days), and increment + ; by one as epoch starts at day 1. + clc + lda ptr1 + adc #1 + sta TM + tm::tm_mday + lda ptr1+1 + adc #0 + sta TM + tm::tm_mday+1 + + ; Now divide the number of remaining seconds by 3600, + ; to get the number of hours, and the seconds in the + ; current hour, in neat 16-bit integers. + + ; Load the previous division's remainder (in ptr2:tmp3:tmp4) + ; as dividend + lda ptr2 + sta ptr1 + lda ptr2+1 + sta ptr1+1 + lda tmp3 + sta sreg + ; We ignore the high byte stored in tmp4 because it will be + ; zero. We'll zero sreg+1 right below, when we'll have + ; a convenient zero already in A. + + ; Load divisor + lda #<3600 + sta ptr3 + lda #>3600 + sta ptr3+1 + + ; Zero the two high bytes of the divisor and the high byte + ; of the dividend. + .if .cpu .bitand CPU_ISET_65SC02 + stz ptr4 + stz ptr4+1 + stz sreg+1 + .else + lda #$00 + sta ptr4 + sta ptr4+1 + sta sreg+1 + .endif + + ; Do the division + jsr udiv32 + + ; Store year + lda #70 + sta TM + tm::tm_year + + ; Store hours (the quotient of the last division) + lda ptr1 + sta TM + tm::tm_hour + lda ptr1+1 + sta TM + tm::tm_hour+1 + + ; Store seconds (the remainder of the last division) + lda ptr2 + sta TM + tm::tm_sec + lda ptr2+1 + sta TM + tm::tm_sec+1 + + ; The rest of the struct tm fields are zero. mktime + ; will take care of shifting extra seconds to minutes, + ; and extra days to months and years. + + ; Call mktime + lda #TM + jsr _mktime + + ; And return our pointer + lda #TM + rts + + .bss + +TM: .tag tm diff --git a/libsrc/common/mktime.c b/libsrc/common/mktime.c index c9ac1652c..7ea3e2bff 100644 --- a/libsrc/common/mktime.c +++ b/libsrc/common/mktime.c @@ -65,7 +65,8 @@ static const unsigned MonthDays [] = { /* Code */ /*****************************************************************************/ - +/* use statics for size optimisation (~34 bytes) */ +#pragma static-locals(push, on) time_t __fastcall__ mktime (register struct tm* TM) /* Make a time in seconds since 1/1/1970 from the broken down time in TM. @@ -74,8 +75,8 @@ time_t __fastcall__ mktime (register struct tm* TM) */ { register div_t D; - static int Max; - static unsigned DayCount; + int Max; + unsigned DayCount; /* Check if TM is valid */ if (TM == 0) { @@ -182,3 +183,5 @@ time_t __fastcall__ mktime (register struct tm* TM) ((unsigned) TM->tm_sec) - _tz.timezone; } + +#pragma static-locals(pop)