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decimal.c
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decimal.c
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/* DECIMAL.C (c) Copyright Roger Bowler, 1991-2009 */
/* ESA/390 Packed Decimal Routines */
/*-------------------------------------------------------------------*/
/* This module contains packed decimal subroutines for ESA/390. */
/* */
/* Acknowledgements: */
/* The lowest level string-math functions are modelled on */
/* algorithms in D.E.Knuth's 'The Art of Computer Programming */
/* Vol.2', and on C.E.Burton's algorithms in DDJ #89. */
/*-------------------------------------------------------------------*/
/*-------------------------------------------------------------------*/
/* Complete rework for reworked instruction decode/execution code */
/* Jan Jaeger 01/07/00 */
/* Add trialrun to ED and EDMK Jan Jaeger 19/07/00 */
/* Fix random MP bug - Mario Bezzi */
/* Clear DXC on data exception - Peter Kuschnerus V209*/
/* z/Architecture support - (c) Copyright Jan Jaeger, 1999-2009 */
/* TP instruction - Roger Bowler 08/02/01 */
/* packed_to_binary subroutine - Roger Bowler 29/06/03 */
/* binary_to_packed subroutine - Roger Bowler 02jul2003 */
/*-------------------------------------------------------------------*/
#include "hstdinc.h"
#if !defined(_HENGINE_DLL_)
#define _HENGINE_DLL_
#endif
#if !defined(_DECIMAL_C_)
#define _DECIMAL_C_
#endif
#include "hercules.h"
#include "opcode.h"
#include "inline.h"
#if !defined(_DECIMAL_C)
#define _DECIMAL_C
/*-------------------------------------------------------------------*/
/* Internal macro definitions */
/*-------------------------------------------------------------------*/
#define MAX_DECIMAL_LENGTH 16
#define MAX_DECIMAL_DIGITS (((MAX_DECIMAL_LENGTH)*2)-1)
/*-------------------------------------------------------------------*/
/* Convert packed decimal number to binary */
/* */
/* This subroutine is called by the CVB/CVBY/CVBG instructions. */
/* It performs the conversion of a 8-byte or 16-byte packed */
/* decimal number into a 64-bit SIGNED binary result. */
/* This routine is not architecture-dependent; all of its operands */
/* are contained in work areas passed by the architecture-dependent */
/* instruction routines which handle all main-storage accesses and */
/* possible program checks. */
/* */
/* Input: */
/* dec An 8 or 16 byte area containing a copy of the */
/* packed decimal storage operand. */
/* len Length-1 (in bytes) of the packed decimal input */
/* (7 for CVB/CVBY or 15 for CVBG). */
/* Output: */
/* result Points to an U64 field which will receive the */
/* result as a 64-bit SIGNED binary number. */
/* ovf Points to an int field which will be set to 1 if */
/* the result overflows 63 bits plus sign, else 0. */
/* If overflow occurs, the result field will contain */
/* the rightmost 64 bits of the result. */
/* dxf Points to an int field which will be set to 1 if */
/* invalid digits or sign were detected, else 0. */
/* The result field is not set if the dxf is set to 1. */
/*-------------------------------------------------------------------*/
void packed_to_binary (BYTE *dec, int len, U64 *result,
int *ovf, int *dxf)
{
U64 dreg; /* 64-bit result accumulator */
int i; /* Loop counter */
int h, d=0; /* Decimal digits */
U64 inter_u64max_div10;
int inter_u64max_rem10;
U64 pos_u64max = 9223372036854775807ULL; // (LLONG_MAX)
U64 neg_u64max = 9223372036854775808ULL; // (LLONG_MIN)
/* Initialize result flags */
*ovf = 0;
*dxf = 0;
/* Initialize 64-bit result accumulator */
dreg = 0;
/* Initialize max unsigned intermediate value for overflow check */
if ((dec[len] & 0x0F) == 0x0B ||
(dec[len] & 0x0F) == 0x0D)
{
inter_u64max_div10 = (neg_u64max / 10);
inter_u64max_rem10 = (int) (neg_u64max % 10);
}
else if ((dec[len] & 0x0F) < 0x0A)
{
*dxf = 1;
return;
}
else
{
inter_u64max_div10 = (pos_u64max / 10);
inter_u64max_rem10 = (int) (pos_u64max % 10);
}
/* Convert decimal digits to binary */
for (i = 0; i <= len; i++)
{
/* Isolate high-order and low-order digits */
h = (dec[i] & 0xF0) >> 4;
d = dec[i] & 0x0F;
/* Data exception if high-order digit is invalid */
if (h > 9)
{
*dxf = 1;
return;
}
/* Check for overflow before accumulating */
if ( dreg > inter_u64max_div10 ||
(dreg == inter_u64max_div10 &&
h > inter_u64max_rem10)) // (NOTE: 'h', not 'd')
{
*ovf = 1;
}
/* Accumulate high-order digit into result */
dreg *= 10;
dreg += h;
/* Check for valid low-order digit or sign */
if (i < len)
{
/* Data exception if low-order digit is invalid */
if (d > 9)
{
*dxf = 1;
return;
}
/* Check for overflow before accumulating */
if ( dreg > inter_u64max_div10 ||
(dreg == inter_u64max_div10 &&
d > inter_u64max_rem10)) // (NOTE: 'd', not 'h')
{
*ovf = 1;
}
/* Accumulate low-order digit into result */
dreg *= 10;
dreg += d;
}
else
{
/* Data exception if sign is invalid */
if (d < 10)
{
*dxf = 1;
return;
}
}
} /* end for(i) */
/* Result is negative if sign is X'B' or X'D' */
if (d == 0x0B || d == 0x0D)
{
/* Check for UNDERflow (less than min negative) */
if ( dreg > neg_u64max )
*ovf = 1;
else
dreg = -((S64)dreg);
}
else
{
/* Check for OVERflow (greater than max positive) */
if ( dreg > pos_u64max )
*ovf = 1;
}
/* Set result field and return */
*result = dreg;
} /* end function packed_to_binary */
/*-------------------------------------------------------------------*/
/* Convert binary number to packed decimal */
/* */
/* This subroutine is called by the CVD/CVDY/CVDG instructions. */
/* It performs the conversion of a 64-bit signed binary number */
/* to a 16-byte packed decimal result. Since the maximum 63 bit */
/* number is less than 31 decimal digits, overflow cannot occur. */
/* Similarly, the maximum 31 bit number is less than 15 decimal */
/* digits, therefore CVD/CVDY can safely use the rightmost eight */
/* bytes of the packed decimal result without risk of overflow. */
/* */
/* This routine is not architecture-dependent; all of its operands */
/* are contained in work areas passed by the architecture-dependent */
/* instruction routines which handle all main-storage accesses and */
/* possible program checks. */
/* */
/* Input: */
/* bin Binary number (63 bits plus sign) */
/* Output: */
/* result Points to a 16-byte field which will receive the */
/* result as a packed decimal number (31 digits + sign) */
/*-------------------------------------------------------------------*/
void binary_to_packed (S64 bin, BYTE *result)
{
int i; /* Array subscript */
int d; /* Decimal digit or sign */
/* Special case when input is maximum negative value */
if ((U64)bin == 0x8000000000000000ULL)
{
memcpy (result,
"\x00\x00\x00\x00\x00\x00\x92\x23"
"\x37\x20\x36\x85\x47\x75\x80\x8D",
16);
}
else
{
/* Load absolute value and generate sign */
if ((U64)bin < 0x8000000000000000ULL)
{
/* Value is positive */
d = 0x0C;
}
else
{
/* Value is negative */
bin = -bin;
d = 0x0D;
}
/* Store sign and decimal digits from right to left */
memset (result, 0, 16);
for (i = 16 - 1; d != 0 || bin != 0; i--)
{
result[i] = d;
d = bin % 10;
bin /= 10;
result[i] |= (d << 4);
d = bin % 10;
bin /= 10;
}
}
} /* end function(binary_to_packed) */
/*-------------------------------------------------------------------*/
/* Add two decimal byte strings as unsigned decimal numbers */
/* */
/* Input: */
/* dec1 A 31-byte area containing the decimal digits of */
/* the first operand. Each byte contains one decimal */
/* digit in the low-order 4 bits of the byte. */
/* dec2 A 31-byte area containing the decimal digits of */
/* the second operand. Each byte contains one decimal */
/* digit in the low-order 4 bits of the byte. */
/* Output: */
/* result Points to a 31-byte area to contain the result */
/* digits. One decimal digit is placed in the low-order */
/* 4 bits of each byte. */
/* count Points to an integer to receive the number of */
/* digits in the result excluding leading zeroes. */
/* This field is set to zero if the result is all zero, */
/* or to MAX_DECIMAL_DIGITS+1 if overflow occurred. */
/*-------------------------------------------------------------------*/
static void add_decimal (BYTE *dec1, BYTE *dec2,
BYTE *result, int *count)
{
int d; /* Decimal digit */
int i; /* Array subscript */
int n = 0; /* Significant digit counter */
int carry = 0; /* Carry indicator */
/* Add digits from right to left */
for (i = MAX_DECIMAL_DIGITS - 1; i >= 0; i--)
{
/* Add digits from first and second operands */
d = dec1[i] + dec2[i] + carry;
/* Check for carry into next digit */
if (d > 9) {
d -= 10;
carry = 1;
} else {
carry = 0;
}
/* Check for significant digit */
if (d != 0)
n = MAX_DECIMAL_DIGITS - i;
/* Store digit in result */
result[i] = d;
} /* end for */
/* Check for carry out of leftmost digit */
if (carry)
n = MAX_DECIMAL_DIGITS + 1;
/* Return significant digit counter */
*count = n;
} /* end function add_decimal */
/*-------------------------------------------------------------------*/
/* Subtract two decimal byte strings as unsigned decimal numbers */
/* */
/* Input: */
/* dec1 A 31-byte area containing the decimal digits of */
/* the first operand. Each byte contains one decimal */
/* digit in the low-order 4 bits of the byte. */
/* dec2 A 31-byte area containing the decimal digits of */
/* the second operand. Each byte contains one decimal */
/* digit in the low-order 4 bits of the byte. */
/* Output: */
/* result Points to a 31-byte area to contain the result */
/* digits. One decimal digit is placed in the low-order */
/* 4 bits of each byte. */
/* count Points to an integer to receive the number of */
/* digits in the result excluding leading zeroes. */
/* This field is set to zero if the result is all zero. */
/* sign -1 if the result is negative (operand2 > operand1) */
/* +1 if the result is positive (operand2 <= operand1) */
/*-------------------------------------------------------------------*/
static void subtract_decimal (BYTE *dec1, BYTE *dec2,
BYTE *result, int *count, int *sign)
{
int d; /* Decimal digit */
int i; /* Array subscript */
int n = 0; /* Significant digit counter */
int borrow = 0; /* Borrow indicator */
int rc; /* Return code */
BYTE *higher; /* -> Higher value operand */
BYTE *lower; /* -> Lower value operand */
/* Compare digits to find which operand has higher numeric value */
rc = memcmp (dec1, dec2, MAX_DECIMAL_DIGITS);
/* Return positive zero result if both operands are equal */
if (rc == 0) {
memset (result, 0, MAX_DECIMAL_DIGITS);
*count = 0;
*sign = +1;
return;
}
/* Point to higher and lower value operands and set sign */
if (rc > 0) {
higher = dec1;
lower = dec2;
*sign = +1;
} else {
lower = dec1;
higher = dec2;
*sign = -1;
}
/* Subtract digits from right to left */
for (i = MAX_DECIMAL_DIGITS - 1; i >= 0; i--)
{
/* Subtract lower operand digit from higher operand digit */
d = higher[i] - lower[i] - borrow;
/* Check for borrow from next digit */
if (d < 0) {
d += 10;
borrow = 1;
} else {
borrow = 0;
}
/* Check for significant digit */
if (d != 0)
n = MAX_DECIMAL_DIGITS - i;
/* Store digit in result */
result[i] = d;
} /* end for */
/* Return significant digit counter */
*count = n;
} /* end function subtract_decimal */
/*-------------------------------------------------------------------*/
/* Divide two decimal byte strings as unsigned decimal numbers */
/* */
/* Input: */
/* dec1 A 31-byte area containing the decimal digits of */
/* the dividend. Each byte contains one decimal */
/* digit in the low-order 4 bits of the byte. */
/* count1 The number of significant digits in the dividend. */
/* dec2 A 31-byte area containing the decimal digits of */
/* the divisor. Each byte contains one decimal */
/* digit in the low-order 4 bits of the byte. */
/* count2 The number of significant digits in the divisor. */
/* Output: */
/* quot Points to a 31-byte area to contain the quotient */
/* digits. One decimal digit is placed in the low-order */
/* 4 bits of each byte. */
/* rem Points to a 31-byte area to contain the remainder */
/* digits. One decimal digit is placed in the low-order */
/* 4 bits of each byte. */
/* Restrictions: */
/* It is assumed that the caller has already verified that */
/* divide overflow cannot occur, that the divisor is not zero, */
/* and that the dividend has at least one high order zero. */
/*-------------------------------------------------------------------*/
static void divide_decimal (BYTE *dec1, int count1, BYTE *dec2,
int count2, BYTE *quot, BYTE *rem)
{
BYTE *num1; /* -> dividend digits */
BYTE *num2; /* -> divisor digits */
int div, flag, scale; /* Work areas for algorithm */
int index, index1, index2; /* Work areas for algorithm */
int indexq, indexr, temp1, temp2; /* Work areas for algorithm */
int temp3, temp4, temp5, qtest; /* Work areas for algorithm */
/* Clear the result fields */
memset (quot, 0, MAX_DECIMAL_DIGITS);
memset (rem, 0, MAX_DECIMAL_DIGITS);
/* If dividend is zero then return zero quotient and remainder */
if (count1 == 0)
return;
/* If dividend is less than divisor then return zero quotient
and set remainder equal to dividend */
if (memcmp (dec1, dec2, MAX_DECIMAL_DIGITS) < 0)
{
memcpy (rem, dec1, MAX_DECIMAL_DIGITS);
return;
}
/* Adjust dividend digit count to give one leading zero */
count1++;
/* Point to significant digits of dividend with leading zero */
num1 = dec1 + MAX_DECIMAL_DIGITS - count1;
/* Point to significant digits of divisor */
num2 = dec2 + MAX_DECIMAL_DIGITS - count2;
scale = 10 / (num2[0] + 1);
if (scale > 1)
{
for (index1 = count1-1, flag = 0; index1 >= 0; index1--)
{
div = flag + scale*num1[index1];
num1[index1] = div % 10;
flag = div / 10;
} /* end for(index1) */
for (index2 = count2-1, flag = 0; index2 >= 0; index2--)
{
div = flag + scale*num2[index2];
num2[index2] = div % 10;
flag = div / 10;
} /* end for(index2) */
} /* end if(scale>1) */
for (index1 = 0; index1 < count1-count2; index1++)
{
if (num2[0] == num1[index1])
qtest = 9;
else
{
temp2 = (index1+1 < count1) ? num1[index1+1] : 0;
qtest = (10*num1[index1] + temp2) / num2[0];
}
temp2 = num1[index1];
temp4 = num2[0];
temp1 = (count2 >= 2) ? num2[1] : 0;
if (index1+1 < count1)
{
temp3 = num1[index1+1];
temp5 = (index1+2 < count1) ? num1[index1+2] : 0;
}
else
{
temp3 = 0;
temp5 = 0;
}
while (qtest*temp1 > (10*(10*temp2 + temp3
- qtest*temp4) + temp5))
--qtest;
for (index = index1+count2, index2 = count2-1, flag = 0;
index >= index1; index--, index2--)
{
if (index2 >= 0)
flag -= qtest*num2[index2];
div = flag + num1[index];
if (div < 0)
{
flag = div / 10;
div %= 10;
if (div < 0)
{
div += 10;
--flag;
}
}
else
flag = 0;
num1[index] = div;
} /* end for(index) */
indexq = MAX_DECIMAL_DIGITS - (count1-count2) + index1;
if (flag != 0)
{
quot[indexq] = qtest - 1;
for (index = index1+count2, index2 = count2-1, flag = 0;
index >= index1; index--, index2--)
{
if (index2 >= 0)
flag += num2[index2];
div = flag + num1[index];
if (div > 9)
{
div -= 10;
flag = 1;
}
else
flag = 0;
num1[index] = div;
} /* end for(index) */
}
else
quot[indexq] = qtest;
} /* end for(index1) */
for (index1 = count1-count2,
indexr = MAX_DECIMAL_DIGITS-count2, flag = 0;
index1 < count1; index1++, indexr++)
{
div = num1[index1] + 10*flag;
rem[indexr] = div / scale;
flag = div % scale;
} /* end for(index1) */
for (index2 = 0, flag = 0; index2 < count2; index2++)
{
div = num2[index2] + 10*flag;
num2[index2] = div / scale;
flag = div % scale;
} /* end for(index2) */
} /* end function divide_decimal */
#endif /*!defined(_DECIMAL_C)*/
/*-------------------------------------------------------------------*/
/* Load a packed decimal storage operand into a decimal byte string */
/* */
/* Input: */
/* addr Logical address of packed decimal storage operand */
/* len Length minus one of storage operand (range 0-15) */
/* arn Access register number associated with operand */
/* regs CPU register context */
/* Output: */
/* result Points to a 31-byte area into which the decimal */
/* digits are loaded. One decimal digit is loaded */
/* into the low-order 4 bits of each byte, and the */
/* result is padded to the left with high-order zeroes */
/* if the storage operand contains less than 31 digits. */
/* count Points to an integer to receive the number of */
/* digits in the result excluding leading zeroes. */
/* This field is set to zero if the result is all zero. */
/* sign Points to an integer which will be set to -1 if a */
/* negative sign was loaded from the operand, or +1 if */
/* a positive sign was loaded from the operand. */
/* */
/* A program check may be generated if the logical address */
/* causes an addressing, translation, or fetch protection */
/* exception, or if the operand causes a data exception */
/* because of invalid decimal digits or sign. */
/*-------------------------------------------------------------------*/
static void ARCH_DEP(load_decimal) (VADR addr, int len, int arn, REGS *regs,
BYTE *result, int *count, int *sign)
{
int h; /* Hexadecimal digit */
int i, j; /* Array subscripts */
int n; /* Significant digit counter */
BYTE pack[MAX_DECIMAL_LENGTH]; /* Packed decimal work area */
/* Fetch the packed decimal operand into work area */
memset (pack, 0, sizeof(pack));
ARCH_DEP(vfetchc) (pack+sizeof(pack)-len-1, len, addr, arn, regs);
/* Unpack digits into result */
for (i=0, j=0, n=0; i < MAX_DECIMAL_DIGITS; i++)
{
/* Load source digit */
if (i & 1)
h = pack[j++] & 0x0F;
else
h = pack[j] >> 4;
/* Check for valid numeric */
if (h > 9)
{
regs->dxc = DXC_DECIMAL;
ARCH_DEP(program_interrupt) (regs, PGM_DATA_EXCEPTION);
return;
}
/* Count significant digits */
if (n > 0 || h != 0)
n++;
/* Store decimal digit in result */
result[i] = h;
} /* end for */
/* Check for valid sign */
h = pack[MAX_DECIMAL_LENGTH-1] & 0x0F;
if (h < 0x0A)
{
regs->dxc = DXC_DECIMAL;
ARCH_DEP(program_interrupt) (regs, PGM_DATA_EXCEPTION);
return;
}
/* Set number of significant digits */
*count = n;
/* Set sign of operand */
*sign = (h == 0x0B || h == 0x0D) ? -1 : 1;
} /* end function ARCH_DEP(load_decimal) */
/*-------------------------------------------------------------------*/
/* Store decimal byte string into packed decimal storage operand */
/* */
/* Input: */
/* addr Logical address of packed decimal storage operand */
/* len Length minus one of storage operand (range 0-15) */
/* arn Access register number associated with operand */
/* regs CPU register context */
/* dec A 31-byte area containing the decimal digits to be */
/* stored. Each byte contains one decimal digit in */
/* the low-order 4 bits of the byte. */
/* sign -1 if a negative sign is to be stored, or +1 if a */
/* positive sign is to be stored. */
/* */
/* A program check may be generated if the logical address */
/* causes an addressing, translation, or protection exception. */
/*-------------------------------------------------------------------*/
static void ARCH_DEP(store_decimal) (VADR addr, int len, int arn, REGS *regs,
BYTE *dec, int sign)
{
int i, j; /* Array subscripts */
BYTE pack[MAX_DECIMAL_LENGTH]; /* Packed decimal work area */
/* if operand crosses page, make sure both pages are accessable */
if((addr & PAGEFRAME_PAGEMASK) !=
((addr + len) & PAGEFRAME_PAGEMASK))
ARCH_DEP(validate_operand) (addr, arn, len, ACCTYPE_WRITE_SKP, regs);
/* Pack digits into packed decimal work area */
for (i=0, j=0; i < MAX_DECIMAL_DIGITS; i++)
{
if (i & 1)
pack[j++] |= dec[i];
else
pack[j] = dec[i] << 4;
} /* end for */
/* Pack the sign into low-order digit of work area */
pack[MAX_DECIMAL_LENGTH-1] |= (sign < 0 ? 0x0D : 0x0C);
/* Store the result at the operand location */
ARCH_DEP(vstorec) (pack+sizeof(pack)-len-1, len, addr, arn, regs);
} /* end function ARCH_DEP(store_decimal) */
/*-------------------------------------------------------------------*/
/* FA AP - Add Decimal [SS] */
/*-------------------------------------------------------------------*/
DEF_INST(add_decimal)
{
int l1, l2; /* Length values */
int b1, b2; /* Base register numbers */
VADR effective_addr1,
effective_addr2; /* Effective addresses */
int cc; /* Condition code */
BYTE dec1[MAX_DECIMAL_DIGITS]; /* Work area for operand 1 */
BYTE dec2[MAX_DECIMAL_DIGITS]; /* Work area for operand 2 */
BYTE dec3[MAX_DECIMAL_DIGITS]; /* Work area for result */
int count1, count2, count3; /* Significant digit counters*/
int sign1, sign2, sign3; /* Sign of operands & result */
SS(inst, regs, l1, l2, b1, effective_addr1,
b2, effective_addr2);
/* Load operands into work areas */
ARCH_DEP(load_decimal) (effective_addr1, l1, b1, regs, dec1, &count1, &sign1);
ARCH_DEP(load_decimal) (effective_addr2, l2, b2, regs, dec2, &count2, &sign2);
/* Add or subtract operand values */
if (count2 == 0)
{
/* If second operand is zero then result is first operand */
memcpy (dec3, dec1, MAX_DECIMAL_DIGITS);
count3 = count1;
sign3 = sign1;
}
else if (count1 == 0)
{
/* If first operand is zero then result is second operand */
memcpy (dec3, dec2, MAX_DECIMAL_DIGITS);
count3 = count2;
sign3 = sign2;
}
else if (sign1 == sign2)
{
/* If signs are equal then add operands */
add_decimal (dec1, dec2, dec3, &count3);
sign3 = sign1;
}
else
{
/* If signs are opposite then subtract operands */
subtract_decimal (dec1, dec2, dec3, &count3, &sign3);
if (sign1 < 0) sign3 = -sign3;
}
/* Set condition code */
cc = (count3 == 0) ? 0 : (sign3 < 1) ? 1 : 2;
/* Overflow if result exceeds first operand length */
if (count3 > (l1+1) * 2 - 1)
cc = 3;
/* Set positive sign if result is zero */
if (count3 == 0)
sign3 = 1;
/* Store result into first operand location */
ARCH_DEP(store_decimal) (effective_addr1, l1, b1, regs, dec3, sign3);
/* Set condition code */
regs->psw.cc = cc;
/* Program check if overflow and PSW program mask is set */
if (cc == 3 && DOMASK(®s->psw))
ARCH_DEP(program_interrupt) (regs, PGM_DECIMAL_OVERFLOW_EXCEPTION);
} /* end DEF_INST(add_decimal) */
/*-------------------------------------------------------------------*/
/* F9 CP - Compare Decimal [SS] */
/*-------------------------------------------------------------------*/
DEF_INST(compare_decimal)
{
int l1, l2; /* Length values */
int b1, b2; /* Base register numbers */
VADR effective_addr1,
effective_addr2; /* Effective addresses */
BYTE dec1[MAX_DECIMAL_DIGITS]; /* Work area for operand 1 */
BYTE dec2[MAX_DECIMAL_DIGITS]; /* Work area for operand 2 */
int count1, count2; /* Significant digit counters*/
int sign1, sign2; /* Sign of each operand */
int rc; /* Return code */
SS(inst, regs, l1, l2, b1, effective_addr1,
b2, effective_addr2);
/* Load operands into work areas */
ARCH_DEP(load_decimal) (effective_addr1, l1, b1, regs, dec1, &count1, &sign1);
ARCH_DEP(load_decimal) (effective_addr2, l2, b2, regs, dec2, &count2, &sign2);
/* Result is equal if both operands are zero */
if (count1 == 0 && count2 == 0)
{
regs->psw.cc = 0;
return;
}
/* Result is low if operand 1 is -ve and operand 2 is +ve */
if (sign1 < 0 && sign2 > 0)
{
regs->psw.cc = 1;
return;
}
/* Result is high if operand 1 is +ve and operand 2 is -ve */
if (sign1 > 0 && sign2 < 0)
{
regs->psw.cc = 2;
return;
}
/* If signs are equal then compare the digits */
rc = memcmp (dec1, dec2, MAX_DECIMAL_DIGITS);
/* Return low or high (depending on sign) if digits are unequal */
if (rc < 0)
regs->psw.cc = (sign1 > 0) ? 1 : 2;
else
if (rc > 0)
regs->psw.cc = (sign1 > 0) ? 2 : 1;
else
regs->psw.cc = 0;
} /* end DEF_INST(compare_decimal) */
/*-------------------------------------------------------------------*/
/* FD DP - Divide Decimal [SS] */
/*-------------------------------------------------------------------*/
DEF_INST(divide_decimal)
{
int l1, l2; /* Length values */
int b1, b2; /* Base register numbers */
VADR effective_addr1,
effective_addr2; /* Effective addresses */
BYTE dec1[MAX_DECIMAL_DIGITS]; /* Operand 1 (dividend) */
BYTE dec2[MAX_DECIMAL_DIGITS]; /* Operand 2 (divisor) */
BYTE quot[MAX_DECIMAL_DIGITS]; /* Quotient */
BYTE rem[MAX_DECIMAL_DIGITS]; /* Remainder */
int count1, count2; /* Significant digit counters*/
int sign1, sign2; /* Sign of operands */
int signq, signr; /* Sign of quotient/remainder*/
SS(inst, regs, l1, l2, b1, effective_addr1,
b2, effective_addr2);
/* Program check if the second operand length exceeds 15 digits
or is equal to or greater than the first operand length */
if (l2 > 7 || l2 >= l1)
ARCH_DEP(program_interrupt) (regs, PGM_SPECIFICATION_EXCEPTION);
/* Load operands into work areas */
ARCH_DEP(load_decimal) (effective_addr1, l1, b1, regs, dec1, &count1, &sign1);
ARCH_DEP(load_decimal) (effective_addr2, l2, b2, regs, dec2, &count2, &sign2);
/* Program check if second operand value is zero */
if (count2 == 0)
ARCH_DEP(program_interrupt) (regs, PGM_DECIMAL_DIVIDE_EXCEPTION);
/* Perform trial comparison to determine potential overflow.
The leftmost digit of the divisor is aligned one digit to
the right of the leftmost dividend digit. When the divisor,
so aligned, is less than or equal to the dividend, ignoring
signs, a divide exception is indicated. As a result of this
comparison, it is also certain that the leftmost digit of the
dividend must be zero, and that the divisor cannot be zero */
if (memcmp(dec2 + (MAX_DECIMAL_DIGITS - l2*2 - 2),
dec1 + (MAX_DECIMAL_DIGITS - l1*2 - 1),
l2*2 + 2) <= 0)
ARCH_DEP(program_interrupt) (regs, PGM_DECIMAL_DIVIDE_EXCEPTION);
/* Perform decimal division */
divide_decimal (dec1, count1, dec2, count2, quot, rem);
/* Quotient is positive if operand signs are equal, and negative
if operand signs are opposite, even if quotient is zero */
signq = (sign1 == sign2) ? 1 : -1;
/* Remainder sign is same as dividend, even if remainder is zero */
signr = sign1;
/* Store remainder into entire first operand location. The entire
field will be filled in order to check for store protection.
Subsequently the quotient will be stored in the leftmost bytes
of the first operand location, overwriting high order zeroes */
ARCH_DEP(store_decimal) (effective_addr1, l1, b1, regs, rem, signr);
/* Store quotient in leftmost bytes of first operand location */
ARCH_DEP(store_decimal) (effective_addr1, l1-l2-1, b1, regs, quot, signq);
} /* end DEF_INST(divide_decimal) */
/*-------------------------------------------------------------------*/
/* DE ED - Edit [SS] */
/* DF EDMK - Edit and Mark [SS] */
/*-------------------------------------------------------------------*/
DEF_INST(edit_x_edit_and_mark)
{
int l; /* Length value */
int b1, b2; /* Base register numbers */
VADR effective_addr1,
effective_addr2, /* Effective addresses */
addr1,
addr2;
int cc = 0; /* Condition code */
int sig = 0; /* Significance indicator */
int trial_run; /* 1=trial run */
int i; /* Loop counter */
int d; /* 1=Use right source digit */
int h; /* Hexadecimal digit */
BYTE sbyte; /* Source operand byte */
BYTE fbyte; /* Fill byte */
BYTE pbyte; /* Pattern byte */
BYTE rbyte; /* Result byte */
SS_L(inst, regs, l, b1, effective_addr1,
b2, effective_addr2);
/* If addr1 crosses page, make sure both pages are accessable */
if((effective_addr1 & PAGEFRAME_PAGEMASK) !=
((effective_addr1 + l) & PAGEFRAME_PAGEMASK))
ARCH_DEP(validate_operand) (effective_addr1, b1, l, ACCTYPE_WRITE_SKP, regs);
/* If addr2 might cross page, do a trial run to catch possible access rupts */
if((effective_addr2 & PAGEFRAME_PAGEMASK) !=
((effective_addr2 + l) & PAGEFRAME_PAGEMASK))
trial_run = 1;
else
trial_run = 0;
for(;trial_run >= 0; trial_run--)
{
/* Initialize variables */
addr1 = effective_addr1;
addr2 = effective_addr2;
cc = 0;
sig = 0;
sbyte = 0;
fbyte = 0;
/* Process first operand from left to right */
for (i = 0, d = 0; i < l+1; i++)
{
/* Fetch pattern byte from first operand */
pbyte = ARCH_DEP(vfetchb) ( addr1, b1, regs );
/* The first pattern byte is also the fill byte */
if (i == 0) fbyte = pbyte;
/* If pattern byte is digit selector (X'20') or
significance starter (X'21') then fetch next
hexadecimal digit from the second operand */
if (pbyte == 0x20 || pbyte == 0x21)
{
if (d == 0)
{
/* Fetch source byte and extract left digit */
sbyte = ARCH_DEP(vfetchb) ( addr2, b2, regs );
h = sbyte >> 4;
sbyte &= 0x0F;
d = 1;
/* Increment second operand address */
addr2++;
addr2 &= ADDRESS_MAXWRAP(regs);
/* Program check if left digit is not numeric */
if (h > 9)
{
regs->dxc = DXC_DECIMAL;
ARCH_DEP(program_interrupt) (regs, PGM_DATA_EXCEPTION);
}
}
else
{
/* Use right digit of source byte */
h = sbyte;
d = 0;
}
/* For the EDMK instruction only, insert address of
result byte into general register 1 if the digit
is non-zero and significance indicator was off */
if (!trial_run && (inst[0] == 0xDF) && h > 0 && sig == 0)
{
#if defined(FEATURE_ESAME)
if (regs->psw.amode64)
regs->GR_G(1) = addr1;
else
#endif
if ( regs->psw.amode )
regs->GR_L(1) = addr1;
else
regs->GR_LA24(1) = addr1;
}