1ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng%default { "naninst":"mvn r0, #0" } 2ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng /* 31465db5ee2d3c4c4dcc8e017a294172e858765cbBill Buzbee * For the JIT: incoming arguments in r0-r1, r2-r3 4ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * result in r0 5ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * 6ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * Compare two floating-point values. Puts 0, 1, or -1 into the 7ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * destination register based on the results of the comparison. 8ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * 9ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * Provide a "naninst" instruction that puts 1 or -1 into r1 depending 10ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * on what value we'd like to return when one of the operands is NaN. 11ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * 12ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * The operation we're implementing is: 13ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * if (x == y) 14ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * return 0; 15ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * else if (x < y) 16ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * return -1; 17ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * else if (x > y) 18ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * return 1; 19ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * else 20ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * return {-1,1}; // one or both operands was NaN 21ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * 22ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * The straightforward implementation requires 3 calls to functions 23ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * that return a result in r0. We can do it with two calls if our 24ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * EABI library supports __aeabi_cfcmple (only one if we want to check 25ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * for NaN directly): 26ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * check x <= y 27ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * if <, return -1 28ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * if ==, return 0 29ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * check y <= x 30ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * if <, return 1 31ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * return {-1,1} 32ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * 33ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng * for: cmpl-float, cmpg-float 34ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng */ 35ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng /* op vAA, vBB, vCC */ 36ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng mov r9, r0 @ Save copies - we may need to redo 37ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng mov r10, r1 381465db5ee2d3c4c4dcc8e017a294172e858765cbBill Buzbee mov r11, lr @ save return address 398b095215a4d5bde723819087f3455bdcc250a78fDavid Butcher ldr ip, .L__aeabi_cfcmple @ cmp <=: C clear if <, Z set if eq 408b095215a4d5bde723819087f3455bdcc250a78fDavid Butcher blx ip 41ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng bhi .L${opcode}_gt_or_nan @ C set and Z clear, disambiguate 42ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng mvncc r0, #0 @ (less than) r0<- -1 43ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng moveq r0, #0 @ (equal) r0<- 0, trumps less than 441465db5ee2d3c4c4dcc8e017a294172e858765cbBill Buzbee bx r11 45ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng @ Test for NaN with a second comparison. EABI forbids testing bit 46ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng @ patterns, and we can't represent 0x7fc00000 in immediate form, so 47ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng @ make the library call. 48ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng.L${opcode}_gt_or_nan: 491465db5ee2d3c4c4dcc8e017a294172e858765cbBill Buzbee mov r0, r10 @ restore in reverse order 501465db5ee2d3c4c4dcc8e017a294172e858765cbBill Buzbee mov r1, r9 518b095215a4d5bde723819087f3455bdcc250a78fDavid Butcher ldr ip, .L__aeabi_cfcmple @ r0<- Z set if eq, C clear if < 528b095215a4d5bde723819087f3455bdcc250a78fDavid Butcher blx ip 53ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng movcc r0, #1 @ (greater than) r1<- 1 541465db5ee2d3c4c4dcc8e017a294172e858765cbBill Buzbee bxcc r11 55ba4fc8bfc1bccae048403bd1cea3b869dca61dd7Ben Cheng $naninst @ r1<- 1 or -1 for NaN 561465db5ee2d3c4c4dcc8e017a294172e858765cbBill Buzbee bx r11 57